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Commercial Hub or Harbor: Trade Routes and Which District to Build

What a trade route actually delivers, where extra route capacity comes from, how to read a city site for Commercial Hub versus Harbor, when a city deserves both, and how to pick destinations and keep traders alive.

What this guide assumes

Gathering Storm rules with the Trading Post mechanics and district adjacency values of the current snapshot. Base-game trade yields differ in detail.
Standard speed on Prince through Emperor. On higher difficulties the AI has more cities and more districts, which makes international routes to its capitals richer, not poorer.
Mixed maps such as Continents or Small Continents where most players own some coast and some river valleys. On Pangaea the Harbor case weakens; on Archipelago it is simply mandatory.

What a Trade Route Actually Delivers

A trade route is a Trader unit walking or sailing between two cities for a fixed number of turns, and the yields it produces are paid to the origin city every turn while it runs. What it pays depends on where it ends. A domestic route, to one of your own cities, pays food and production, and the amount grows with the number and kind of districts standing in the destination. An international route, to another civilization or a city-state, pays mostly gold, again scaled by the destination's districts, with small side yields such as science from a Campus or culture from a Theater Square at the far end. The direction matters: the destination's districts decide the yield, but the origin city collects it.

Three side effects matter as much as the yields. First, a Trader lays road along its path, and the road quality improves with the era, so a route between two of your cities is also the cheapest way to connect them for troop movement. Second, when a route completes, a Trading Post appears in the destination city; any later route that passes through a city holding one of your Trading Posts gains extra gold and can reach further, which is how a chain of posts extends your reach across a continent. Third, an active route to another civilization nudges your tourism toward that civilization, which is a quiet bonus for culture players.

The Trader's range is limited, and the route panel only lists cities it can reach. Coastal cities with a Harbor can send Traders over water, which opens destinations that a land route could never touch, while a landlocked city is confined to whatever it can walk to. This single fact decides more Harbor-or-Hub debates than any adjacency number does, because a Hub in a city with no reachable foreign destinations produces gold only from its own buildings.

Where Route Capacity Comes From

Trade route capacity is the number of routes you may run at once, and it is empire-wide rather than per city. The first slot arrives with the Foreign Trade civic, which is also what unlocks the Trader. After that the standard sources are the Market in a Commercial Hub and the Lighthouse in a Harbor, and here is the rule that matters: a city gets one slot from these buildings, not two. A city with both a Market and a Lighthouse contributes the same single slot as a city with only one of them. Capacity therefore scales with the number of cities holding either district, which is the strongest argument for putting one of the two in every city rather than both in a few.

Wonders and great people add slots on top. The Colossus, which must stand on coast beside land and next to a Harbor, grants a slot and a free Trader, and the Great Zimbabwe, which wants cattle and a Commercial Hub beside it, grants a slot plus extra gold on routes leaving its city. Several Great Merchants add a slot when activated, Zhang Qian and Marco Polo among them, and a Great Admiral or two does the same, which is one reason the Harbor's admiral points are not wasted on a peaceful player. Some governments add capacity as well, Merchant Republic most famously.

A few civilizations rewrite the ledger. Mansa Musa's Mali gains capacity as it enters Golden Ages and squeezes extra gold from desert origins, and its Suguba replaces the Commercial Hub with cheaper purchases attached. Portugal's international routes are restricted to coastal and Harbor destinations but pay heavily for it, and its Trader range at sea is unusually long.

Foreign Trade civic: the first slot and the Trader itself.
Market or Lighthouse: one slot per city, never two from the same city.
Colossus and Great Zimbabwe: a slot each, with a free Trader and route gold respectively.
Great Merchants such as Zhang Qian and Marco Polo, and select Great Admirals: a slot on activation.
Governments and leader abilities: Merchant Republic and Mansa Musa's Golden Ages add capacity on top.

Reading a City Site: Hub or Harbor

The Commercial Hub's adjacency is simple: a river beside it is worth two gold, an adjacent Harbor is worth two more, the Government Plaza adds one, and every pair of other adjacent districts adds one. The Harbor's is just as short: two gold for touching the city center, one for every adjacent sea resource, one from the Government Plaza, and one per pair of adjacent districts. Put the two side by side and the site reads itself. A city on a river bend, where a Hub tile can touch water on two sides while sitting next to the center and a future Campus, is a Hub city. A city whose coast has two or three fish, crabs, or whales in a cluster next to a center-adjacent coast tile is a Harbor city.

Beyond adjacency, each district brings things the other cannot. The Harbor lets the city build ships even when the center is a tile inland, lets its Traders sail, removes the embark penalty for units leaving it, and its Lighthouse and Seaport add housing that a Hub city has to find elsewhere. Its Shipyard converts the district's gold adjacency into production, which means a Harbor with three sea resources and a neighbouring center is a production district in disguise. The Commercial Hub, in return, is the Great Merchant engine, is cheaper to reach in the tech tree via Currency than the Harbor via Celestial Navigation for a civ beelining land techs, and its Bank and Stock Exchange are the stronger late gold buildings.

One hazard is specific to the Hub. On a river with floodplains, a Hub placed on the floodplain tile can be pillaged by a flood until a Dam stands upstream, and a pillaged district pays nothing until repaired. If the only river tiles are floodplains, either accept a few pillage events, plan the Dam early, or take the Harbor and let the river be for farms. The Harbor has its own exposure, covered under trader protection below: coastal barbarian camps spawn ships that raid harbors and routes alike.

When a City Wants Both

Since a city only ever contributes one route slot from its Market or Lighthouse, the second district is never about trade capacity. It is about adjacency and buildings. The Hub gains two gold from touching the Harbor and the Harbor gains from the district pair, so a coastal capital at a river mouth can run both at high adjacency, collect Great Merchant and Great Admiral points in the same city, put a Shipyard's production and a Bank's gold under one set of policy cards, and still only use one slot. That is a good deal in a city that will build eight or nine districts anyway. It is a poor deal in a six-population city that could have spent the same production on a Campus.

The test is whether the city has more district slots than it has good uses for them. Capitals and any city that reaches double-digit population before the Renaissance usually pass it. Border cities, filler cities, and cities founded mainly to claim a luxury usually fail it, and for those the answer is the single district that reaches the most destinations, which on a coast is often the Harbor even when the river adjacency looks better on paper.

Unique districts shift the calculation. Phoenicia's Cothon is a Harbor that also feeds the adjacent Hub, England's Royal Navy Dockyard does the same while paying its own gold, and the Netherlands' Harbors claim nearby tiles the moment they are placed, so those three civs want both in more cities than average. Mali's Suguba makes the Hub side cheaper to buy out and rewards Holy Site and river neighbours, so a Mali coastal city can reasonably put the Suguba first and the Harbor later, the reverse of the usual coastal order.

Picking Destinations: Gold Versus Food and Production

The best destination depends on what the origin city is short of, not on what the route panel highlights. A freshly founded city with two population and no districts is short of everything except ambition; send its route to your own capital or largest city, because a domestic route pays the origin food and production according to the destination's districts, and the capital has the most. Three or four such routes are how a new city cluster reaches its second district a dozen turns earlier. Once the origin city is grown and building on its own, flip its route to an international destination and take the gold.

For gold, the rule of thumb is districts and posts. Among reachable foreign cities, the one with the most districts pays the most base gold, and any route that passes through cities already holding your Trading Posts collects extra along the way, so a distant capital reached via two of your posts often beats a nearer city with a shorter path. City-states are respectable gold destinations early, and a route to a city-state also completes fast enough to plant a post there for later chaining. Sort the route panel by gold, then check whether the top entry runs through territory you can actually keep a Trader alive in.

Governors and policies tilt individual routes. Magnus's Surplus Logistics promotion sweetens every domestic route that ends in his city, which is one more reason to park him in the capital during the expansion phase and aim new cities' routes at him.

New or stalled city as origin: domestic route to the city with the most districts, usually the capital.
Developed city as origin: international route to the district-rich foreign city, preferably via your own Trading Posts.
Early game with few slots: a short city-state route plants a Trading Post fast and extends later range.
Culture plan: keep at least one route running to the civ whose tourism resistance you most need to erode.
Never leave a slot idle; a mediocre route plus a per-route policy beats no route.

Keeping Traders Alive

A Trader dies the moment a hostile unit uses the plunder action on a tile its route passes through, and the plunderer pockets gold for the trouble. Barbarians do this constantly, and they do not respect borders. The practical defence is not escorting the Trader, which is slow and rarely coincides with the route, but removing the threat: clear every barbarian camp within reach of a route's path before the route starts, keep a mounted unit patrolling the corridor your routes share, and prefer routes that run through your own or an ally's improved territory, where sentries and city strikes make raids expensive.

Sea routes have their own predators: barbarian galleys and quadriremes from coastal camps, and later privateers. A Harbor city that sends its Traders to sea should keep one or two ships of the current era nearby, and should hunt any coastal camp on the same landmass as a priority, since those camps keep spawning raiders for as long as they stand. Suzerainty over Lisbon makes your Traders immune to plunder on water tiles, which for a maritime economy is worth more than most other city-state bonuses combined and justifies spending envoys there early.

War changes the map instantly. Routes to a civilization you go to war with are cancelled, and a Trader caught inside now-hostile territory is a free kill for whoever finds it first. Before declaring, or when a denouncement suggests someone is about to declare on you, re-route Traders whose paths cross the likely enemy and accept a worse destination for the duration.

How the Choice Feeds Science and Culture Plans

The two districts feed different great person races. Commercial Hubs and their buildings generate Great Merchant points, and the merchants are the most economically useful great people in the game: extra route slots, luxuries, envoys, gold, and policy slots depending on the era. Harbors and their buildings generate Great Admiral points, which peaceful players often dismiss, yet a few admirals add route capacity or gold and all of them can be retired for a burst of gold if nothing else. A player who wants merchants should concentrate Hubs and Markets early.

Gold is the currency every plan converts to. A science plan needs Libraries and Universities in six cities on the same turn, and gold buys buildings outright while production cannot be moved between cities. With Reyna's Contractor promotion the same gold buys districts, which turns a strong trade economy into instant Campuses in freshly founded cities and collapses the usual thirty-turn lag between settling and researching. Culture plans use gold the same way for Amphitheaters and Museums, and lean on the tourism nudge from international routes as a second dividend. Whichever district a city builds, the routes it enables are what pay for the rest of the empire's districts.

The district choice also shapes the tech path. A Harbor-first coastal empire reaches Celestial Navigation and then Shipbuilding early, which happens to line up with Cartography and the exploration bonuses, while a Hub-first empire tends to sit in Currency and Apprenticeship and reach the Industrial Zone sooner. Neither path is wrong, but knowing which one your districts have committed you to keeps the tech tree tool on this site honest: plan the next ten techs around the districts you actually built, not the ones you meant to.

Mistakes That Waste a Trade Economy

Trade mistakes are quiet because a bad route still pays something. The player running four international routes for gold while three new cities starve at size two, the player who built both districts in every coastal city expecting doubled capacity, and the player whose Traders die every fifteen turns to the same barbarian camp are all earning less than half of what their slots could return. Audit the route list every era: count idle slots, count routes that no longer match their origin's needs, and count Traders lost since the last check.

Building Harbor and Commercial Hub in the same small city for a second route slot that does not exist.
Running gold routes from cities that still need food and production to reach their second district.
Choosing the Hub for a coastal city with no reachable land destinations, then wondering why its routes pay little.
Starting long routes through unexplored land before the barbarian camps along the way have been cleared.
Leaving a slot idle for ten turns while waiting for a perfect destination to come into range.
Placing the Hub on a floodplain with no Dam planned, then losing its yields to every second flood.

Last reviewed: 2026-09-03 · Based on game-data snapshot gs-1.0.12.68-build15296837