Frank Hugh Hann (19 October 1846–23 August 1921) was an explorer in Western Australia, who in 1897 named Lake Disappointment. Hann was in the area exploring the east Pilbara, around Rudall River. He noticed creeks in the area flowed inland, and followed them expecting to find a large fresh water lake. To his disappointment the lake turned out to be salt.
He was the son of Joseph ( - 3 January 1864) and Elizabeth ( - 24 June 1864) Hann. Fellow explorer William Hann was his older brother.
Hann named McFadden Ranges on Friday, 23 April 1897 - Hann stated in his diary "the range SSW from here I will call the McFadden, as he was one of the Waters Party". The range was named after a prospector who was with a prospecting party led by Waters. Hann commented in his diary before naming the feature "Saw old horse dung here, must be the same as we saw on the Rudall, I think Waters and party. I went up creek to range about one and a half miles to range, a nice pool of water in gorge, about six months water. I will call this creek the Waters and Waters Pool."[1]
Frank Hann National Park and Hann River are both named in his honour.