Topographic Map of Japan, 1/25,000 scale ウォッちず 国土地理院地図閲覧サービス
Offered by the Geographical Survey Institute; Map of Japan in 1/25,000 scale is viewable.
JapanMap View Japan with many layers of information, including nuclear power plants, the railway network, local fire stations, etc. Originally created by Lex Berman after the 2011 triple disaster.
東京関係地図目録 Catalogs of Tokyo/Edo maps.
東京都公立図書館住宅地図総合目録 Union catalog of Tokyo residential maps from the Tokyo Public Library.
Historical Maps 歴史地図
Japanese Maps of Tokugawa Era University of British Columbia's 275 maps are viewable.
国会図書館絵図検索 535 historical maps are searchable, some with images.
Complete Survey of the Japanese Coast 大日本沿海輿地全図
The first geographical survey maps of Japan, made by Tadataka Ino, and often known as the Ino maps 伊能図. This site provides digital images of 43 sheets, as well as options to view the entire map (some sheets have been lost) and to zoom in. There is also a comprehensive geographical name index including old, modern, and natural place names. Created by the National Diet Library.
国立公文書館絵図（江戸時代） Edo period maps and images from the National Archive of Japan.
Harvard Map Collection: Japan related Enter "Japan" in the search field. Includes 81 viewable images.
Gaihōzu: Japanese Imperial Maps
外邦図研究プロジェクト led by Prof. Shigeru Kobayashi, Osaka University. 『外邦図研究ニューズレター 』is available in pdf.
アメリカ議会図書館蔵初期外邦測量原図データベース Early Japanese Military Maps of Korea and China held by LC
Gaihōzu: Japanese Imperial Maps 120 sets of maps held by the Stanford University are viewable.
Secret Japanese Military Maps Could Open a New Window on Asia's Past by Greg Miller in National Geographic (Aug. 2016)