Delaware By hiddenvalley5 Jan 14, 1609 hudson descovers delaware bay May 14, 1754 first library in delaware May 14, 1777 Dover becomes a capital Dec 7, 1787 admited in union Jan 1, 1793 yellow fever swee[ps through the coast Mar 17, 1829 delaware cannal opens Jan 20, 2009 joe biden became the first senator from delaware for vice president