Maureen:
I have little info..but my great-grandmother was Annie Monaghan Reilly and when her son, "Henry" John Reilly married Loretta Doyle, in 1911, he was living at 109A Bergen St.
Other streets where my line lived in Brooklyn were...Warren, Wyckoff, Hicks, Coles, President, 4th, Dean, to name a few.
Were your Monaghans involved in the Electrical Business?