Melania Trump's Hometown in Slovenia Going All Out to Celebrate Next First Lady (PHOTO)

Melania Trump will become the second First Lady since 1825 to have been born outside the U.S. ... and her hometown in Slovenia's ready to party it up in her honor.

We're told the mayor in Melania's hometown of Sevnica -- a small town of about 5,000 people -- is so fired up the entire town's getting in on the festivities.

For starters, the landmark Sevnica Castle -- a big tourist attraction -- will offer free admission and tours. The main event will be a YUUUGE inauguration viewing party at Rotary klub Sevnica.

Then ... free dinner at the local inn (but $40 donations would be nice) ... and all the loot will go toward buying new equipment for the Sevnica Hospital ER.

As for what's the grub -- a mix of Slovenian and American cuisine.

BTW ... John Quincy Adams' wife, Louisa Catherine, who was born in London, was previously the first and only First Lady born outside the U.S.