A previous version of Lone Star Tick Simulation Model (LSTSIM) for a wildlife ecosystem was revised and expanded to include a beef cattle forage area and improved handling of tick-host-habitat interactions. Relationships between environmental and biological variables were also refined in the new version. General validity of the revised model was established by comparing simulated and observed host-seeking populations of Amblyomma americanum (L.) at five geographic locations, three in Oklahoma and two in Kentucky-Tennessee. Additional validity was indicated from comparisons of simulated and observed seasonality of lone star ticks at one location in Kentucky. The model produced acceptable values for initial population growth rate, generation time, and 15-yr population density when historical weather files for 14 locations in the United States were used. The model of A. americanum population dynamics was used to study the relationship between tick density and density of white-tailed deer, Odocoileus virginianus (Zimmerman), and cattle. The revised model can be used for additional simulation studies on effects of tick control technologies and integrated management strategies.