Lakes bathymetry is a line feature-based layer that includes bathymetric information for selected reservoirs, lakes, and ponds in Montana. The layer is based on information collected by multiple sources including contractors with Montana Department of Environmental Quality, the Bureau of Reclamation, and Montana Fish, Wildlife & Parks. Data collection methods vary over time with techniques using a variety of different equipment including manual and electronic depth soundings, use of a GPS receiver, and digitizing previously published bathymetry maps. Data were compiled at a variety of scales and resolutions, depending on the collection method used for a particular waterbody. These data are planned to be regularly updated, however bathymetry information for addtional waterbodies may become available and included in this layer as new information is collected and compiled.