e/Foundation Day (Western Australia)

Information
has gloss	eng: Foundation Day, officially June 1, but celebrated on the first Monday in June, is a public holiday in Western Australia (WA), commemorating the foundation of the Swan River Colony in 1829. Because of the celebration of Foundation Day, Western Australia is the only State or Territory of Australia which does not celebrate the Queens (or Kings) Birthday Holiday in June — it is held in September or October instead.
lexicalization	eng: Foundation Day
instance of	c/June observances