In almost every Presidential campaign, some genealogist will release a chart showing that the opposing candidates are nth cousins or are both related to George Washington or to Abraham Lincoln.
The problem is if you had ancestors in what is now the US in colonial times but they didn't live in the New England colonies, that the records will be too incomplete to trace all the lineages. A lot of Virginia records were destroyed when Richmond burned in 1865.
William and Mary College, the second oldest institution of higher learning in what is now the US, was named for a king and queen who were first cousins. The first Queen Mary also married her first cousin, Philip II.