Figure 7.3 Municipal organization and urban growth in Portland, 1940-60.pdf

Note: While before 1940 most physical urban development had occurred within the corporate boundaries of Portland, Milwaukie, and Oregon City, extensive residential subdivision occurred in unincorporated portions of Multnomah, Clackamas, and Washington Counties between 1940 and 1960. Boundaries of incorporated municipalities circa 1961 are overlaid. Municipal boundaries are approximate – comparison of contemporaneous maps suggests that the smaller municipalities undertook a number of annexations in the early 1960s.https://ir.lib.uwo.ca/shapingthemetropolis/1023/thumbnail.jp