The United Thank Offering is a ministry of the Episcopal Church at the national level for the mission of the entire church. Its history flows out if its origins as representing the ministry of Episcopalian women during a time when they were not able to participate in the decision making bodies of the church. As that has changed, the ministry of the UTO has not abated, but has rather expanded to include a myriad of expressions. Trinity has recently begun to participate in their yearly ingathering, held each autumn.
For more information, see http://www.episcopalchurch.org/page/united-thank-offering.