United States electoral votes aren't distributed completely proportionally to state population. This is because the number of electors for a state is determined by adding the number of respresentatives and senators. Since there are always at least 2 senators and 1 representative, smaller states can have nearly 3x as much voting power as larger states on a per-capita basis.

This visualization shows the number of "weighted votes" a citizen has in each US state. This is determined as follows:

Weighted Votes = (Total US Population / Total US Electoral Votes) / (State Population / State Electoral Votes)

The national average number of weighted votes per person is 1, but some states have as much as 3 per person and some fewer than 1.