PLYMOUTH, Mass. — Here in the birthplace of Thanksgiving, where the Pilgrims first gave thanks in 1621 for their harvest and their survival, some residents are giving thanks this year for something else: the Colonial-era blue laws that prevent retailers from opening their doors on the fourth Thursday of November.

While shoppers in the rest of the country will skip out on Thanksgiving to go to Walmart or Kmart or other big-box stores, William Wrestling Brewster, whose ancestors arrived on the Mayflower and participated in that first Thanksgiving, will limit his activities to enjoying a traditional meal here with his extended family at his parents’ house.

“Thanksgiving is supposed to be about giving thanks for all you have,” said Mr. Brewster, 47, who runs a computer repair business. “I cringe to think what society is doing to itself,” he said of the mercantile mania that threatens one of the least commercial holidays.

Some of the nation’s biggest retailers — Sears, Target and Toys “R” Us among them — announced this month that they would be moving up their predawn Black Friday door-buster sales to Thanksgiving Day or moving up their existing Thanksgiving sales even earlier on Thursday. Walmart, which has already been open on Thanksgiving for many years, is advancing its bargain specials to 8 p.m. Thursday from 10 p.m.