This data set contains climate, flux, and bulk density data from Ivotuk and Council (Seward Peninsula), Alaska, collected from 1998 through 2000. Surface energy and trace gas exchange measurements were made at each of the four Ivotuk sites using the eddy covariance technique. Three flux and climate towers operated at Council, Seward Peninsula, during 1999 and 2000. Two towers were located at the tundra and forest sites. The third tower was a mobile tower and during 1999 covered four different surface types: lowshrub, shrub, woodland, and burned tundra. During 2000, the mobile tower covered tall shrub, tundra ISS2, burned tundra, heath and shallow thaw lake. The data have been divided by surface type or site and by data type (flux or climate). The data set also includes mean bulk density measurements for soil layers, collected in 1999. Measurements were taken as part of the Land-Atmosphere-Ice Interactions Arctic Transitions in the Land-Atmosphere System (LAII-ATLAS) program. The research project was funded by the Arctic System Sciences (ARCSS) Program, grant number OPP-9818066. Data are available by FTP.