The Socialist Party will hold a national convention in Milwaukee, Wisconsin, October 16-18, 2015. The party’s national web page has a form, asking individuals who wish to seek the party’s presidential nomination to apply on-line.
The Socialist Party is recognized by the Federal Election Commission as a national committee. However, it is not currently ballot-qualified in any state.
Other presidential party nominating conventions for 2016 include:
Green Party, August 4-7, 2016, in Houston, TX.
Constitution Party, April 13-16, 2016, in Salt Lake City, Utah.
Libertarian Party, May 26-30, 2016 in Orlando, Florida.
Democrats and Republicans will nominate in July 2016.