Schwartz (1941), Dalke and Sime (1938), Dalke (1937 and 1942), Hendrickson (1936), and Allen (1939) estimated the home range of the cottontail by drawing, on a map, straight lines that connected all marginal points of capture in live-traps. The resulting home ranges were polygonal figures. Haugen (1942) altered this method by drawing lines that connected points midway between the actual points of capture and the next outermost traps in the grid. Fitch (1947) used a method for enclosing all points of capture in a circle or ellipse that represented the home range boundaries and expressed home range as the diameter of these figures. Another method, which has been used to determine the home range of birds, is to map the movements of an individual as it is observed. Stebler (1939) suggested the use of tracking records to determine home range. Connell (1954) expressed home range of cottontails as the average distance traveled from a computed center of activity. The method was originally proposed by Hayne (1949). The methods used by other investigators to calculate the home range of the cottontail have yielded estimates varying from 0.1 acre to 100 acres. Such wide variations in the estimated size of home range may result from the use of different methods and from insufficient data. The data obtained from live-trapping are not fully adequate because traps cannot sample, in time and space, the entire home range of an individual. Also, "trap habit" or "trap shyness" may distort the apparent shape of the home range. In order to compare these methods I have calculated home range from my data by each of five different methods. The results are shown in Table 1. No two methods yielded exactly the same results. To utilize all available data for each individual, I recorded on a map the locations of capture in live-traps, nests and forms, locations where the animal was observed in the field and the routes that it took between them. At the end of the study a line was drawn on the map to enclose the areas where the cottontail was known to have been. Live-traps were operated intermittently at 130 stations between December 8, 1954, and February 10, 1956. Sixteen cottontails were marked in the same area by Robert L. Packard in 1954. Data from 7850 trap nights were used in this study. The traps were set at fifty-foot intervals and the pattern approximated that of a grid in habitat favorable for cottontails such as at edges of woodland. In wooded areas traps were placed at fifty-foot intervals parallel to the edges. Traps were not set on areas of poor habitat where neither cottontails nor their sign were observed. The traps were operated eight to twelve days and closed for two to five days intermittently throughout the trapping period except in the months of April to August, 1955, when trapping was unsuccessful because the cottontails then were not attracted by bait.