Alexanders Blockhouse was a two storied log structure built in response to the Indian War of 1855-56 on Whidbey Island by John Alexander, an early settler. It was later moved to the city of Coupeville where it is preserved.
When the settlers along Penn Cove decided that their safety required a blockhouse, they helped Alexander build one. As soon as they completed their double story fort of tightly fitted logs, they then surrounded it with a ten foot high double stockade.
The second floor of the blockhouse was high enough to see over the stockade. The walls were notched out so that if necessary riflemen could fire at any possible attackers. Broken glass and metal fragments were imbedded in the top of the stockade as added deterents to stockade climbing. (Herbert Hart, Pioneer Forts of the West. p. 88.)