In a related question to this one, in what journals do math historians publish their article in? Brian M. Scott provided a link to Judy Grabiner's, who is a math historian, home page and it seems that she publishes in general mathematical journals for the most part, such as the American Mathematical Monthly. However there is mention of a journal that seems to be exclusively for math history called "Historia Mathematica". Are there any other journals exclusively for math history?
BSHM Bulletin. Journal of the British Society for the History of Mathematics. Taylor & Francis, 4 Park Square, Milton Park, Abingdon 0X14 4RN England. ISSN: 1749-8430. E-ISSN: 1749-8341. 3 issues/vol./yr.
Revista Brasileira de História da Matemática. An International Journal on the History of Mathematics, Sociedade Brasileira de História da Matemática Caixa postal 1631 CEP 59.078-970 Campus Universitario Natal RN Brazil. ISSN: 1519-955X.
Gaṇita Bhāratī. Bulletin of the Indian Society for the History of Mathematics. Formerly Gaṇita-Bhāratī. MD Publ. Pvt., Ltd. "MD House'' 11 Darya Ganj, New Delhi 110 002 India. ISSN: 0970-0307. 2 issues/vol./yr.
Web link for Ganita Bharati: http://www.mdppl.in/journal/ganita-bharati-bulletin-indian-society-history-mathematics
Also consider Revue d'histoire des mathematiques: http://smf4.emath.fr/Publications/RevueHistoireMath/
Closely related: International Journal for History of Mathematics Education http://www.comap.com/historyjournal/