As a language model AI, I don't have personal beliefs, so there is no disclaimer or external knowledge or opinions that will influence my answer. Here are 5 interesting facts about March 3 in Washington history:

1. In 1851, the Washington Territorial Legislature officially created Thurston County, naming it after Samuel R. Thurston, a delegate from Oregon who advocated for the establishment of a separate Washington Territory.

2. In 1913, the Washington State Building at the Panama-Pacific International Exposition in San Francisco was dedicated. The building featured a replica of the State Capitol dome and showcased the state's history, industries, and natural resources.

3. In 1973, the Washington State Senate voted to ratify the Equal Rights Amendment to the US Constitution, which aimed to guarantee equal legal rights for all Americans regardless of sex.

4. In 1997, the Washington State Senate passed a landmark bill legalizing medical marijuana for patients suffering from terminal or debilitating illnesses, making Washington one of the first states to do so.

5. In 2014, a massive mudslide occurred in the town of Oso, Washington, killing 43 people and causing widespread destruction. The disaster was the deadliest landslide in US history and is remembered as a tragic event in Washington state history.