The Circle B Bar Reserve is an area of protected lands in Polk County, Florida. Comprising 1,267 acres at 4399 Winter Lake Road (SR 540) near Lakeland, Florida, the area is managed by the Polk County Board of County Commissioners (BOCC). It is jointly owned by the BOCC and the Southwest Florida Water Management District. The park was purchased in 2000 for $7.4 million using funds provided by an environmental lands acquisition referendum approved by voters in 1994.