マンホールコレクション is a free iPhone app developed by Atsushi Ezaki, categorized under Travel & Navigation. The app features a collection function that allows users to manage and record the collection of manhole cards from the 1st to the 21st edition, along with their location and distribution information. Users can also register manholes beyond the cards. Additionally, the app offers a map function where users can view card information and registered items on a map.

The registration process is simple, primarily requiring a photo and location information, with additional customization through tags for shape and type. Users can easily filter and search for specific items, making organization straightforward.