Concord: These bluish purple, full-bodied grapes were first grown in Concord, Mass., but New York is now second (behind Washington state) in production. In 1869, Thomas Bramwell Welch (sound familiar?) pressed this grape into unfermented juice. It's still the base of Welch's grape juice.
Niagara: This variety was created in Niagara County, NY, in 1868 and is considered the white-skinned counterpart to Concord. It is also used in juice, mostly white grape juice (including Welch's). Niagaras are pale green, sweet, and aromatic. They don't travel well, so you rarely see them far from where they're grown.
Himrod: These pale, yellowish green grapes are small and seedless. They were created in Geneva, New York as part of the Cornell University grape breeding program in 1952. Himrods grow in large, bountiful clusters and have a sweet, honey-like flavor.