Proper noun
おかやまけん
岡山県には、土地特有の建築物はありますか？
Is there any vernacular architecture in Okayama prefecture?
Okayama (岡山) Prefecture is a prefecture in Japan. Learning the reading will help you to remember the meaning of this word since half of it is in Japanese.
The reading is the kun'yomi readings of the first two kanji. Luckily you learned them when you learned the kanji. Then, stick 県 on there and you should be good to go!