I'm reading the Japanese Graded Readers from White Rabbit Press. One of them takes place in a town called 緑町, which is glossed (in furigana) as みどりまち.
However, I looked this town up, and both the Japanese and English versions of Wikipedia claim it's pronounced みどりちょう. Which is correct, or are both? Did the book make a mistake, or are there two alternate pronunciations?
One place has basically only one name, and it can be written both in Kanji and in Hiragana. But, there are many place names in Kanji which are shared among places with different pronunciation. For example, there is 三田(みた) in Tokyo, and 三田(さんだ) in Hyogo.
Japanese Wikipedia also has several examples.
よく知られた語と違う読みをする例
「彦山（ひこやま、ひこさん）」、「八幡（はちまん、やはた、やわた）」、「名東（めいとう、みょうどう）」、「大山（おおやま、だいせん）」、「川内（かわうち、せんだい）」、「国府」（こくふ、こくぶ、こう）、「府中」（ふちゅう、こう）、「国分」（こくぶん、こくぶ）、「富田」（とみた、とみだ、とんだ）、「富山」（とやま、とみやま）、「外山」（とやま、そとやま、とのやま）など、まったく違う複数の読みがある地名も、片方しか知らない人物にとっては他方が難読となる。
