According to Wikipedia, John Kennedy has a town in Brazil named for him.
The question didn’t specify a U.S. town.
There’s also a city in Liberia named after Buchanan, and I’m fairly sure it’s named after the US president. And as is well known, Monrovia, Liberia is named after James Monroe. Besides the other two mentioned in this thread, are there any other foreign cities named after US presidents?
TrickTrivia: What’s the largest city in the US named after a president?
Houston is the US’ 4th largest city and is named for Sam Houston, president of the Republic of Texas from 1836-1844.
Kudos to you. You saw through my trick question.
Well, I started thinking “big cities,” and Houston popped up in my mind, and then I thought, “Wasn’t old Sam president of Texas for awhile?”
You are cordially invited to buy me a BBQ dinner if we ever meet in Lockhart, TX. I’ll pop for beer. 
I wonder if there are any prior Rotary, student council, etc. presidents who would qualify.
Another major recent naming, although not after a U.S. President: the King County, Wash. (greater Seattle area) government kept the same name but made it clear that the county was named after Martin Luther King Jr. and not after (as had originally been the case) William R. King, Franklin Pierce’s short-lived VP (who served only from March 4-April 18, 1853).
From Wikipedia:
In honor of his inauguration as Vice President, the newly formed Washington Territory was named King County for him, as well as Pierce County after President Pierce, in hopes of gaining speedy admission to the Union by currying favor with the new administration (Washington did not become a state until 1889). King County still exists, but on February 24, 1986 the county council passed Motion 6461, “setting forth the historical basis for the ‘renaming’ of King County in honor of Reverend Dr. Martin Luther King, Jr.” On April 19, 2005, Washington State Governor Christine Gregoire signed Senate Bill 5332 into law, formalizing the prior resolution and officially designating King County’s name to be in honor of Martin Luther King.
To date, this seems the winner to the OP question.
I disagree. The OP said town or county named after a US president.
Presidente Kennedy, in Brazil is a town that meets the OP’s constraints.
Kennedy, Minnesota goes back at least to 1910.
Kennedy, Alabama goes back at least to 1895.
Depending on how fast and loose you want to define a town, the USS Ronald Reagan, with a population of just under 5,700 officers and crew (including the Air Wing, with it’s 2,480 personel), could be considered a fairly recent town named after President Reagan, but I’ll admit this could be considered cheating in regards to answering the OP’s question 
Just a nitpick: Houston was actually president of Texas from 1836-1838 and 1841-1844. Sandwiched in between was Mirabeau B. Lamar. Under the Texas constitution, presidents served for 2 years and were precluded from serving consecutive terms (though there were no term limits otherwise).
:smack: Okay, beer and sides.
In my own defense, I real quicklike Googled up Sam’s terms so as to present a more thoroughly trivia-geek answer, and skimmed the first site I hit, thereby missing Mr. Lamar entirely.
You saved my house for me. Thanks. I was flying blind when I made that boast, but was so close to certain that I felt brave enough to make that claim.
As an aside/hijack, is there any reliable website that gives the dates for the naming of towns, counties and such? It would surprise me to think that places newly formed enough to bear the names of 20th century personages would be listed somewhere, as though the phenomenon would be site-worthy. Just asking.
Say, that’s just about the time that the town of Lamar Texas was founded.
Coincidence? 
Roosevelt, New Jersey was also named after FDR.
If the Texas president was limited to non-consecutive two-year terms, how did Sam Houston serve from 1841 to 1844? Did they change the rule at some point?
They changed the election timing, holding an election in Dec. 1941 and Dec. 1944, giving Houston a longer term, but he did not succeed himself. Note that Lamar, who held the office between Houston’s two terms, also served for 3 years. I don’t know whether the election was delayed until 1944 for circumstantial reasons, or a deliberate change in procedure. Or if it was the 1940 election which was delayed until 1941 while Lamar was was in office. Or if the term wasn’t strictly two years to begin with. I’m sure somebody else does.