Stop the Surge of Unsafe Rio Grande Encampments Act of 2021 or the Stop the SURGE Act of 2021 This bill requires the Department of Homeland Security (DHS) to transfer certain aliens who enter the United States unlawfully to new ports of entry. Specifically, if DHS encounters such an individual in certain Border Patrol sectors (generally the sectors covering Texas), DHS must immediately transfer the individual to new ports of entry established under this bill in specified locations, including Greenwich, Connecticut, and Martha's Vineyard, Massachusetts. DHS may not exercise discretion to process such individuals in any location other than the ports of entry created under this bill. These provisions shall be deemed to have taken effect on September 1, 2021.