We report 23 new heat flow values in the state of Oklahoma and combine these with previously reported values to create heat flow maps of Oklahoma and the central United States. In general, thermal gradients increase from southwestern Oklahoma (minimum, 14 ¿C km-1) to northeastern Oklahoma (maximum, 42 ¿C km-1); the mean thermal gradient in central Oklahoma is 31 ¿C km-1. We made 1498 thermal-conductivity measurements on drill cuttings from oil and gas wells. Heat flow in Oklahoma varies between 22 and 86 mW m-2; the average is about 50 mW m-2. Heat flow is relatively low (30--40 mW m-2) in southwest Oklahoma and is relatively high (70--80 mW m-2) in one section of east central Oklahoma. We also report 27 new estimations of radioactive heat production in basement rocks and combine these with 22 previously published data to create a map of basement heat production in Oklahoma. Heat production values range from 1.1 to 3.5 μW m-3, with an average of 2.5 μW m-3. Geologic evidence suggests that the present-day thermal regime is not significantly affected by sedimentation, erosion, or metamorphic/igneous activity and is essentially in a near steady state condition. Heat flow in Oklahoma appears to be largely controlled by heat production in basement rocks, although the correlation between heat flow and heat production is not strong. An area of high heat flow (70--80 mW m-2) in east central Oklahoma may be related to regional groundwater flow through the Arbuckle-Simpson aquifer. ¿ 1998 American Geophysical Union