The limits within which the total precipitation as measured by a single gage represents the total precipitation over the surrounding area is a subject of great interest to hydrologists and meteorologists. The lack of adequate data from large areas has made detailed analytical studies impossible. The precipitation‐gage network established during the period from 1935 to 1940 in the Muskingum River Watershed in Ohio by the U.S. Soil Conservation Service provides data for limited studies for a 8038‐sq mi area. Records from 230 gages for a full year beginning October 1, 1939; are available. The data from these stations have been used by the authors to analyze the effect of gage spacing on the accuracy of determination of the amount of annual precipitation for areas in Ohio ranging in size from a few square miles to 8000 sq