Despite its remote location, Alamo Lake State Park receives relatively large numbers of visitors in the mild seasons of spring, winter and fall, mostly because of the good fishing it offers - bass and catfish are especially plentiful. The reservoir was formed in 1968 by the construction of Alamo Dam for flood control purposes on the Bill Williams River, and is now the fifth largest in Arizona, though as with all Southwest lakes, the surface area varies a lot from year to year.