What was the purpose of committiees of correspondence

The Maryland Committee of Correspondence was instrumental in setting up the First Continental Congress, which met in Philadelphia. These served an important role in the Revolution, by disseminating the colonial interpretation of British actions between the colonies and to foreign governments.

president thomas jefferson commissioned the expedition shortly after the louisiana purchase in 1803 to explore and to map the newly acquired territory, to find a practical route across the western half of the continent, and to establish an american presence in this territory before britain and other european powers

i believe we're not a republic so that is a hard question