' s , ▁Philadelphia ' s , ▁San ▁Francisco ' s , ▁and ▁Washington , ▁D . C .' s ▁combined ▁Jewish ▁populations . ▁ ▁The ▁number ▁of ▁Jews ▁in ▁New ▁York ▁City ▁so ared ▁throughout ▁the ▁beginning ▁of ▁the ▁ 2 0 th ▁century ▁and ▁reached ▁a ▁peak ▁of ▁ 2 ▁million ▁in ▁the ▁ 1 9 5 0 s , ▁when ▁Jews ▁constit uted ▁one - qu arter ▁of ▁the ▁city ' s ▁population . ▁New ▁York ▁City ' s ▁Jewish ▁population ▁then ▁began ▁to ▁decl ine ▁because ▁of ▁low ▁fert ility ▁rates ▁and ▁migration ▁to ▁sub ur bs ▁and ▁other ▁states , ▁particularly ▁California ▁and ▁Florida . ▁Though ▁there ▁were ▁small ▁Jewish ▁communities ▁throughout ▁the ▁United ▁States ▁by ▁the ▁ 1 9 2 0 s , ▁New ▁York ▁City ▁was ▁home ▁to ▁about ▁ 4 5 % ▁of ▁the ▁entire ▁population ▁of ▁American ▁Jews . ▁A ▁new ▁wave ▁of ▁Ash ken azi ▁and ▁B uk har ian ▁Jewish ▁imm igr ants ▁from ▁the ▁former ▁Soviet ▁Union ▁began ▁arriv ing ▁in ▁the ▁ 1 9 8 0 s ▁and ▁ 1 9 9 0 s . ▁Se ph ard ic ▁Jews , ▁including ▁Sy rian ▁Jews , ▁have ▁also ▁lived ▁in ▁New ▁York ▁City ▁since ▁the ▁late ▁ 1 9 th ▁century . ▁Russian , ▁Lith uan ian , ▁and ▁Polish ▁Jews ▁imm igr ated ▁during ▁this ▁mid - 1 9 th ▁Century ▁as ▁well , ▁in ▁large ▁numbers . ▁Many ▁Jews , ▁including ▁the ▁newer ▁imm igr ants , ▁have