Lake Havasu City is a year-round resort community in Mohave county in western Arizona residing in the Chemhuevi Valley along the Colorado River , west of the Mohave Mountains. Founded in 1964, it was promoted by industrialist Robert P. McCulloch as the focal point of a recreational and retirement development, and it soon became the county's largest community. It centers on the 45-mile- (72-km-) long Lake Havasu, impounded by Parker Dam and 3 miles (4.8 km) across at its widest point, and London Bridge . The latter was designed by John Rennie with multiple masonry arches and completed in 1831 over the River Thames in London. It was disassembled in 1968-71, its marble facing transported over sea and land, and reerected to span a man-made inlet on the Colorado River. Dedicated in 1971, it has generated unusual tourist interest. Havasu National Wildlife Refuge is to the north, and Lake Havasu State Park is across the lake in San Bernardino county, California. In addition to tourism and services, manufacturing (notably chain saw and watercraft production) is a major source of employment, and cattle ranching is a basic economic activity in the surrounding region.