[2] Pelham was born in Ottawa, Ontario, coming to New York City when his father opened an architectural office there in 1875.
The elder Pelham designed for the city's Department of Public Parks, and employed his son as a draftsman in his firm.
[4] In 1905, he designed the Riverdale apartment building at 67 Riverside Drive for developer John Louis Miller.
For many years the office was at 200 West 72nd Street, originally built as a clubhouse for the Colonial Club of New-York.
Pelham, like Rosario Candela, chose that address because a number of developers had their offices there, including Paterno & Son and Anthony Campagna.