Trentwood joined the other unincorporated communities in the region to form the city of Spokane Valley in 2003.

Rather than a centralized town, East Trent was a loose collection of communities including a rail station named Steno, after a local court stenographer, and Trentwood Orchards, so named because of an economy of lumber and fruit trees.

In 1917, after the stenographer died as well as many of the fruit trees, the railroad and communities came together under the name Trentwood.

There were 1,632 housing units at an average density of 923.2 per square mile (356.4/km2).

18.2% of all households were made up of individuals, and 4.4% had someone living alone who was 65 years of age or older.