Addy was first settled in 1851 by Magnus Flett, a Hudson's Bay Company (HBC) employee, after he retired to the Addy area. Thomas Stensgar retired from the Hudson's Bay Company in 1852 and obtained the first homestead in the area in 1867.
Addy became the stop between Chewelah and Colville on the Spokane Falls and Northern Railroad at the end of March 1892. Addy was platted by G. Fatzer in 1893. In 1975, Alcoa built a magnesium smelter , which became the largest employer in the county. In 2001, Alcoa closed the plant due to unfavorable market conditions.
The first school was built in 1884 under Stevens County District 11. In 1967, the last Addy school was closed and students were bused to Chewelah.
A small town alongside State Route 395, Addy was not tracked by the 2000 U.S. Census, but in the 2010 census the population was 265. The town has one gas station, and a coffee shop. There is one restaurant in town, although several other businesses cater to the primarily agricultural local economy. Addy is assigned the ZIP code 99101.
This climatic region is typified by large seasonal temperature differences, with warm to hot (and often humid) summers and cold (sometimes severely cold) winters. According to the Köppen Climate Classification system, Addy has a humid continental climate, abbreviated "Dfb" on climate maps.
- "Boom Town Tales". Retrieved 31 July 2016.
- Lives Lived West of the Rockies: A biographical Dictionary of Fur Traders Working West of the Rockies, 1793-1858 by Bruce Watson
- "IIS7". Retrieved 31 July 2016.
- Colville Republican newspaper 25 March 1892 Pg 8
- Colville Republican newspaper 4 February 1893 Pg 2
- Historylink.org Stevens County Article
- "Alcoa: News: News Releases: Alcoa Shuts Down Northwest Alloys Magnesium Smelter". Retrieved 31 July 2016.
- The Last Bell by Alpha Naff, Northeast Washington Genealogical Society 2005, ISBN 0-9705654-1-0
- "Addy, Washington Köppen Climate Classification (Weatherbase)". Retrieved 31 July 2016.