Oregonlive, the online blog for the Oregonian (Portland’s local paper) has a brief write-up on Columbia City:
Photo: Oregonlive
Between downtown and the airport, Columbia City (read about it on the Visit Seattle web site) is the most interesting stop along Seattle’s Central Link light rail line for visitors.
The heart of the designated national historic district lies a three-block walk east of the Columbia City light rail stop, via Edmunds Street from the station on Martin Luther King Way to the business district in Rainier Avenue South. A half mile farther east is Seward Park, the city park on a peninsula in Lake Washington.
Columbia City was once its own incorporated city, but voted to join Seattle in 1903. Now it is part of Rainer Valley, which is one of 65 or so neighborhoods in Seattle…
Columbia City Source 
they got the date wrong, but oh well.
“Columbia incorporated as “Columbia City” in January 1893. Annexation to the City of Seattle came May 3, 1907″