The center, which has kept track of such groups for 30 years, recorded 1,018 hate groups operating last year.
The number of groups whose ideology is organized against specific racial, religious, sexual or other characteristics has risen steadily since 2000, when 602 were identified, the center said. Antigay groups, for example, have risen to 27 from 17 in 2010.
The report also described a “stunning” rise in the number of groups it identifies as part of the so-called patriot and militia movements, whose ideologies include deep distrust of the federal government.
In 2011, the center tracked 1,274 of those groups, up from 824 the year before.