Ketchikan is located at 55°22′52?N, 131°39′51?W on Revillagigedo Island, 90 miles (145 km) north of Prince Rupert, British Columbia and 235 miles (378 km) south of Juneau, Alaska.

According to the United States Census Bureau, the City has a total area of 4.1 mi² (10.7 km²). 3.4 mi² (8.7 km²) of it is land and 0.8 mi² (2.0 km²) of it (18.60%) is water.

Average annual rainfall is 152 inches (3861 mm); annual average snowfall is 37 inches (940 mm). The average high temperature in July is 57 degrees Fahrenheit (14 degrees Celsius), and the average high temperature in January is 33 degrees Fahrenheit (0.5 degrees Celsius).

In August, 2005 the 2005 Highway Bill provided for $223m in subsidies to build a bridge nearly as long as the Golden Gate Bridge (dubbed by critics as the “Bridge to Nowhere”) between Ketchikan and nearby Gravina Island (population: 50).

The subsidies were negotiated by Alaska’s Rep. Don Young. It was hoped that the bridge would help spawn development on the island, which houses the city’s airport.