Harbor

Information

Adjacency Bonuses:

• +1 Gold from every 2 adjacent district tiles
• +1 Gold from each adjacent coastal resource tile
• +2 Gold from each City Center Tile
• +1 Gold from each adjacent Government plaza tile

Yields (Per Citizen):

1. +2 Gold
2. +1 Science

Trade Yields:

• Domestic:

1. +1 Production

• Foreign:

1. +3 Gold

Currently Harbors and Commercial Hubs are arguably the most impactful early game districts because of the Medieval Era dedication Free Inquiry. If you can get them online by that point and you can get the Civic Naval Tradition to use the Civic Card Naval Infrastructure to get to Field Cannons (Ballistics) up to Artillery (Steel) before the Medieval Era ends.

This alone is reason to prioritize them as soon as possible but they are so feature packed that it's nearly impossible to play a game without getting them first. Here's a list of some of their strong points:

1. Flexibility: Each trade route is essentially another citizen working for your city -- for any of your cities you choose, which yields Food, Production, Science, Culture, Gold, Faith at your leisure
2. No maintenance cost: The Harbor and Commercial Hubs Districts are the only two to my knowledge which do not cost you gold per turn to maintain -- neither the district itself nor the district buildings. In fact instead of costing you gold per turn they give you gold per turn
3. High Adjacencies: With +2 being standard for putting a harbor adj to any of your cities, more from sea resources and other bonuses you can use them as a base district with which to get tons of era score boosts and flat yields to progress further in the game
4. Making Sea settles stronger: The district buildings of Harbors will enhance the power of your coastal cities via making the tiles yield more gold and food, making them workable

Issues:

1. Positioning: The harbor is extremely poorly positioned on the technology tree because of the mandatory goals of multiplayer early game play -- Your first goal is to get up your defenses... unfortunately the technologies required to get those are on the other side of the technology tree (Horseback riding/iron working)
2. Jack of all master of none syndrome: The harbor is a cool quasi-hybrid of all the other districts -- it impacts units, trade, growth, production, science. So while it's strongish to help improve your coastal cities it has no true extreme strengths -- it doesn't even have a city-state type to help boost its yields

Harbor Buildings

Tier 1

Tier 2

Tier 3

End