Some Calvinists, sometimes called four-point Calvinists, reject the doctrine of limited atonement. Another group, known as Hyper-Calvinists, hold beliefs above and beyond this, such as the position that God has also predestined some to Hell (the doctrine of reprobation), that it is wrong to evangelize, because God will save His own, and that God does not command everyone to repent, only the elect (those whom He has chosen.)
Websites of Interest Calvinist Denominations
The Protestant Reformed Churches in America (PRC) http://prca.org One of the most conservative Reformed (another term for Calvinist) denominations in the world, the PRC separated from the CRC in the 1920's in a schism over the issue of common grace. Most of its member churches are in West Michigan, Iowa, and other places where there are Christian Reformed congregations. The Christian Reformed Church in North America (CRC) http://www.crcna.org The CRC is a conservative/evangelical denomination founded by Dutch immigrants in the nineteenth century in West Michigan. It has many congregations in Michigan, Iowa, California, southwest Ontario, and elsewhere. The Reformed Church of America (RCA) http://www.rca.org The RCA is a liberal/evangelical denomination formed by Dutch immigrants during colonial times. The Presbyterian Church in the USA (PC(USA)) http://www.pcusa.org One of the largest denominations in the US, the PC(USA) has over a million members. It is a liberal, mainline denomination with roots in England and Scotland. Contrast with Arminianism.