Costco opened five new stores in November across North America, including three in the United States and two in Canada. As of January 5, 2026, Costco has 639 locations across the country, with West Virginia, Wyoming, and Rhode Island among the states without a warehouse.

All grocery stores will be open in New Jersey and the greater metropolitan area on Martin Luther King Jr. Day 2026

While Costco warehouses are closed on many major holidays throughout the year, stores will remain open on Martin Luther King Jr. Day. The wholesaler will operate during normal business hours on Monday, Jan. 19. Since hours vary among locations, confirm your local Costco's open and close times before going.

Martin Luther King Jr. Day is observed on Monday, Jan. 29, 2026. Several federal offices and services will be closed, and most people have off for the holiday. However, many retail stores will be open and operating according to their usual business hours. So if you want to do some shopping on Martin Luther King Jr. Day, you’re in luck.