Before 1913 North Interstate Avenue was called North Patton Avenue after Matthew Patton.  Matthew Patton's family owned land in the West Hills and North Portland but then the street was connected to a new bridge over the Columbia River.  I guess the City Council felt that a name change was in order.   

Once upon a time there were three cities called Portland, East Portland and Albina.  In 1891 these cities were combined to make Portland forcing The Great Renaming.  Over the years after Portland became one big city, Eastside Portlanders became resentful that their streets started with "east" while West Portland streets had no directional description.  So in 1933 all the streets were given the N, NW, SW, SE and SW declaration. 

German sounding names were changed during World War I, like Frederick which was named after Frederick the Great, King of Prussia.  It was decided that it sounded better as Pershing in honor of the general who was leading the Americans.

MLK Jr. Blvd used to be Union Avenue but in 1989 Martin Luther King Junior needed to be recognized.  

Part of Front Ave was changed to Naito Parkway the year Bill Naito died, 1996.  Bill was a developer and civic leader whose company was on Naito Parkway along with the Japanese-American Historic Plaza.    

Last year marked the death of Rosa Parks who has long been known as one of the great Civil Rights leaders.  In her honor North Portland Boulevard was renamed Rosa Parks Way. 

Source: Eugene Snyder's book, "Portland Street Names and Neighborhoods" for the early history