USACO meaning in Regional ?

The United States of America Computing Olympiad (USACO) is an online computer programming competition, which serves as qualification for the International Olympiad in Informatics (IOI) in the United States. Primarily for secondary school students in the United States, the USACO offers four competitions (December, January, February, US Open) during the academic year. Participants compete in four increasingly difficult divisions: Bronze, Silver, Gold and Platinum;, coding & submitting computer programs in one of four languages: C, C++, Java, and Python. Competitors advance through the levels by performing well in their current division.

Following the US Open(ran in April) competition, a week-long summer training camp is held in early summer(with around 16-24 top USACO participants invited as USACO "Finalists"). Four students are selected from a group of finalists to represent the United States of America(USA) at the International Olympiad in Informatics (IOI). All expenses are paid for the training camp and competition at IOI.