Results are presented from analyses of jet data produced in pp̅ collisions at √s=630 and 1800 GeV collected with the DØ detector during the 1994–1995 Fermilab Tevatron Collider run. We discuss the details of detector calibration, and jet selection criteria in measurements of various jet production cross sections at √s=630 and 1800 GeV. The inclusive jet cross sections, the dijet mass spectrum, the dijet angular distributions, and the ratio of inclusive jet cross sections at √s=630 and 1800 GeV are compared to next-to-leading-order QCD predictions. The order αs3 calculations are in good agreement with the data. We also use the data at √s=1800 GeV to rule out models of quark compositeness with a contact interaction scale less than 2.2 TeV at the 95% confidence level.