LAMARC is a program which estimates population-genetic parameters such as population size, population growth rate, recombination rate, and migration rates. It approximates a summation over all possible genealogies that could explain the observed sample, which may be sequence, SNP, microsatellite, or electrophoretic data. LAMARC and its sister program Migrate are successor programs to the older programs Coalesce, Fluctuate, and Recombine, which are no longer being supported. The programs are memory-intensive but can run effectively on workstations.