A 2.43-ha deer exclosure was constructed in the Tennessee Valley Authority’s Land Between The Lakes in 1977–78 to study the effects of deer exclusion on the lone star tick, Amblyomma americanum (L.). Tick populations were monitored with dry ice in 1978 and 1979, and with dry ice and drags in 1982. Lone star tick larvae averaged 98% fewer on exclosed plots than on control plots for all 3 study years. Populations of overwintered nymphs and adults were reduced by acaricide application and showed no significant differences in 1978. For 1979 and 1982, nymphs averaged 38% fewer on exclosed plots. Adults averaged 22% fewer on exclosed plots for 1979 and 1982; however, this difference was not significant. Reinfestation of the exclosure by adults and nymphs was attributed to movement of small host animals between the exclosed and adjacent untreated areas. A possible exclosure response was also observed in the American dog tick, Dermacentor variabilis (Say), in that the exclosed field became more infested with adult American dog ticks than the other areas.