Support for legislation to have the federal government take land in trust for the Mashpee Wampanoag Tribe has grown in recent months as the tribe and others wait to see if Congress will schedule committee hearings to take up two identical bills, which aim to end an ongoing legal challenge to the tribe’s reservation.

Tribal nations, cities and towns from across the country have written to congressional leaders urging them to vote the bills — both called the Mashpee Wampanoag Tribe Reaffirmation Act — out of committee. Lawmakers have received 26 letters of support from pan-tribal organizations, tribes and nonprofit groups, including 21 from individual tribes.

Some of the organizations backing the legislation include the United South and Eastern Tribes, representing more than 20 tribes, including the Wampanoag Tribe of Gay Head Aquinnah; the National Indian Gaming Association, which represents 184 federally recognized tribes; and the Apache Alliance, representing Apache Tribes in Arizona, New Mexico and Oklahoma.

The legislation, introduced by U.S. Rep. William Keating, D-Mass., in the House and U.S. Sen. Edward Markey, D-Mass., in the Senate, seeks to resolve the ongoing legal challenge to the Cape-based tribe’s reservation land brought by neighbors of a $1 billion resort-casino project slated for land the federal government had previously agreed to take into trust in Taunton.

The number of lawmakers co-sponsoring the House bill has also grown to 18. But support for the Senate bill appears to be lacking, with Markey and U.S Sen. Elizabeth Warren, D-Mass., still the only sponsors, according to Congress’s website.