Final answer:
Richmond, Virginia is the state capital located on the East Coast of the United States, which is historically significant and part of the densely populated Northeast region.
Step-by-step explanation:
The East Coast of the United States is the region along the Atlantic Ocean. Given the choices of state capitals, Richmond, Virginia is the one located on the East Coast. It was essential historically, as the Northeast is the most densely populated area of the country, with a significant historical role since the colonial era. Although Washington, D.C. is today the national center of government without natural defenses, early colonies like Virginia were instrumental in developing representative democratic governments. Furthermore, the geographical location of cities and states played a decisive role in their development and defense capabilities, as exemplified by the growth of New York City, aided by its break of bulk advantages and the Erie Canal.