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In grazing behavior studies, livestock within the same pasture usually are not considered as independent experimental units because of potential social interactions among individuals. However, treating individual animals as independent experimental units in extensive rangeland pastures may be useful for some experimental designs. The objective of this study was to evaluate the association patterns among Global Positioning System (GPS) tracked cattle grazing at 6 different study sites in the western United States. Association among 11 to 17 GPS-tracked cows grazing in herds ranging from 37 to 250 cows were analyzed over 33 to 90 d periods using the computer program ASSOC1. Half-Weight Index (HWI) association values were calculated for each pair of GPS-tracked cows (i.e., dyad) at each study site to determine the proportion of time cattle were within 75 m and 500 m from each other. Cattle at 2 study sites exhibited relatively low mean HWI-association values (i.e. less than 0.23 HWI at 500 m); whereas, associations at the other study sites tended to have greater mean HWI associations (i.e., greater than 0.35 HWI at 500 m). Distinguishing features between study sites that had low and high association values were management of cattle prior to the study, herd size, pasture size, and number of watering points. At 5 of the 6 study sites, at least 75 % of all dyads had HWI association values less than 0.5 at 500 m, indicating that most of the GPS-tracked cows were greater than 500 m from each other for over 50 % of tracking period. While interactions among cattle in the same pasture are often inevitable, movement patterns of a sub-set of individual GPS-tracked cows grazing in extensive pastures may have levels of independence sufficient to be considered as individual experimental units under some situations.