Cleveland, for the 2016 Republican National Convention . It'll also be earlier than in the past, late June or mid July. It was down to Cleveland and Dallas. As one who will be covering it, I was rooting for Dallas (no offense Cleveland), but an Ohio city, of course, makes a lot of sense. But I'm not sure how much hosting a convention does toward getting a state's electoral votes.
And Dallas could have been seen as Hispanic outreach. The earlier date is probably more important than the location; it allows the GOP candidate to start spending earlier on the general election, something that the party believes hurt Mitt Romney in 2012.
Photo credit: By Joanne (Flickr: Oh beautiful city!) [CC-BY-2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons