Nevada, Iowa, is pronounced nuh-VAY-da instead of nuh-VAA-da.
Buena Vista (at least the college, maybe the county, too) is pronounced BYOO-na VIS-ta instead of BWAY-na VIS-ta (they get angry up there if you pronounce it like it's Spanish).
Madrid, Iowa, is pronounced MAD-rid instead of ma-DRID.
Fun fact: when I was an air traffic controller in Cedar Rapids some years back, a pilot checked in for VFR flight following. I asked what his destination was, and he said "Mack-uh-WEE-ta." It took me a second to figure out he meant Maquoketa.
You can blame Uncle Charles for Madrid. He hated not only his in-laws but also his hired man who constantly bragged about being from Madrid, Spain.
Boone County’s Towns and Cities
Madrid, located in present day Douglas Township, is the oldest town in Boone County. The first resident of Boone County, Charles W. Gaston of Pennsylvania, settled in the Madrid area in 1846 where he married his second wife, Anna C. Dalander.. The Dalanders, Swedish natives, had immigrated to the area in 1846 and were the recipients of Boone County’s first land deed in 1849. Swede Point, now part of Madrid, was first surveyed in May of 1851 and officially filed for record in February of 1852. Other plats for the town were filed in 1853, 1855 and 1857. Gaston later was responsible for giving Madrid its Spanish name. According to the 1914 History of Boone County, Gaston was named the executor of his mother-in-law’s estate. He argued with some of the family, and “out of resentment to them he changed the name [of Swede Point] to Madrid. About the time of this change Mr. Gaston had in his employ a Spaniard, who often spoke of Madrid, the capital of his native country. He [Gaston] held the Spaniard, his country and capital, all in contempt; so to get even with his Swedish brothers, he took from the town its Swedish name and substituted for it the Spanish name.”