Alonso Cook's early jobs included serving as a probate judge in the Idaho Territory, working as an attorney for the state of Washington, and also practicing as a physician. While in Vancouver, Washington, the Cook family resided briefly in the historic Charles Brown House, built in 1866, possibly by Alonzo himself. The unique French Second Empire type architecture of the house suggests Alonzo may have built it since this type of construction typically hails from where Alonzo came from, the east coast. French Second Empire architecture is rare on the west coast.
Garden Grove founded
In 1874, the Cooks bought 160 acres (0.65 km2) of land  that was sold secondhand from the once-dominant Abel Stearns Ranch. The land covered what is now the area of Lampson Street to Garden Grove Boulevard and from Euclid/Main Street to Nutwood Street. There were only a few hundred people living on farms around the area at the time.
After their house was completed in 1874, Cook commenced the establishment of a civic center, the start of commerce, and a school district for the area. Cook donated all the land needed for these facilities, which were the first semblances of a village he named "Garden Grove". The local citizens did not like this name because it consisted of open fields.
By 1877, the village had a church, a blacksmith, a post office and a general store. By 1881, the Cook family moved on to pursue interests in other states and other enterprises.
Cook, the son of Gerry and Mary Cook, met his future bride, Belle Webster in 1860 while he was attending the Ohio State University and she was teaching in Iowa. They married in 1861 when he was 22 years old and she was 18. The Cooks had one daughter, whom they named Marabell.
Following their marriage, Cook continued with his education. He had attended Ohio State University as well as Union Law School, which is now Northwestern University. Throughout their marriage, Cook and his wife relocated on several occasions, living in Iowa, Idaho, Oregon, Washington, and California.
- Alonzo Cook Retrieved: 2010-03-22. Archived 2011-07-08 at the Wayback Machine
- HISTORY Retrieved: 2010-03-22. Archived 2010-01-20 at the Wayback Machine
- Alonzo Cook Retrieved: 2010-03-22.
- Welcome to Key to the City's page for Garden Grove Retrieved: 2010-03-22.
- "Archived copy". Archived from the original on 2009-04-08. Retrieved 2009-08-11.CS1 maint: Archived copy as title (link) HEADLINE HISTORY Orange County 1866 to 1888
- City of Garden Grove Retrieved: 2010-03-22'
- Ibid. Retrieved: 2010-03-22. Archived 2011-07-08 at the Wayback Machine
- Doig, Leroy L., The Village of Garden Grove – 1870-1905. Orange, CA: The Paragon Agency, 2000.
- Head, H. C., The History of Garden Grove. Garden Grove, CA: The Garden Grove News, 1939.