The single-non-transferrable plurality-winner voting method commonly used in the United States, and the spoiler effect that can produce, helps cement a two-party system that many people (including some leading candidates) in that country are quite unhappy with.
Yet there are plenty of other voting systems, like the Single Transferrable Vote method used to elect moderators on Stack Exchange sites, where voters can honestly indicate their top preference and have an incentive to do so, without the disincentive that this might help their least favored candidate win.
Are there jurisdictions in the US that allocate elected positions (and/or Electoral College electors) based on a system other than a plurality vote where each voter can indicate support for just one candidate?
Note: I am not talking about multi-winner districts, such as when voters select more than one "at large" representative, if those are selected as simply the top n with the highest vote counts.
Also, I'm restricting the scope of the elections to public office, rather than leadership elections which may occur within private organizations.