All of the towns annexed had a city council and mayor. To join Seattle, a petition of at least 20 percent of the town's voters was presented to their respective councils, which were then required to call for an election to vote on dissolving the town and annexing to Seattle. If the vote was favorable and the City of Seattle approved, the town would be annexed.
Following is a list of the towns with their size and the official date of their annexation to Seattle.
- Southeast Seattle (5.73 sq. miles) January 7, 1907
- Ravenna (0.62 sq. miles) January 15, 1907
- South Park (0.87 sq. miles) May 3, 1907
- Columbia (1.12 sq. miles) May 3, 1907
- Ballard (3.71 sq. miles) May 29, 1907
- West Seattle (16.34 sq. miles) July 24, 1907
In all, the area of Seattle nearly doubled, increasing from 35.09 square miles to 67.10 square miles. The city continued to annex adjoining areas and by 1954 had increased in size to 91 square miles.