Subsurface temperature and thermal gradients along a north-south cross section through the Arkoma Basin and the Oklahoma Platform in southeastern Oklahoma were estimated from 345 bottom hole temperatures from 199 oil and gas wells. The average geothermal gradient in the southern part of the basin near the Ouachita Front is 20 ¿C/km, exceeds 30 ¿C/km in the middle part of the basin, and is 24 ¿C/km on the Oklahoma Platform to the north. Drill cuttings obtained from 11 oil and gas wells were used for 843 thermal conductivity measurements. Thermal conductivity data, corrected to in situ conditions, were used to estimate heat flow. Estimated heat flow (¿20%) in the deep part of the Arkoma Basin near the Ouachita Front is 35--40 mW/m2 and increases systematically northward to 60--65 mW/m2 on the Oklahoma Platform. Average heat production, estimated from gamma ray logs, is 2.3¿0.2 μW/m3 for basement rocks underlying the Arkoma Basin and 2.8¿0.1 μW/m3 for basement rocks in the Oklahoma Platform area. Numerical models show that heat refraction from the less conductive sedimentary rocks (~1.6 W/m ¿K) of the Arkoma Basin to the more conductive crystalline rocks (~3.0 W/m ¿K at 25 ¿C) of the Oklahoma Platform and the Ouachita Mountains accounts for about 5--10 mW/m2 of the observed 20--30 mW/m2 decrease in heat flow from north to south. Changes in crustal heat production related to compositional changes and crustal thinning account for another 5--15 mW/m2 of the observed heat flow change. If the remaining 0--20 mW/m2 difference in heat flow is attributed to heat transport by topographically driven groundwater flow, the average basin-scale permeability of the Arkoma Basin and the Oklahoma Platform can be no greater than 10-15 m2. Results of this study are not generally supportive of theories which invoke topographically driven regional groundwater flow from the Arkoma Basin in Late Pennsylvanian-Early Permian time (~290 Ma) to explain the genesis of Mississippi Valley-type lead-zinc deposits, paleothermal anomalies, and regional diagenesis in the North American midcontinent. ¿ American Geophysical Union 1996