Jeff Miller posted requesting information about "fraternal lodges of
mutual aid, benevolent, sick-and-benefit, burial and free loan
societies formed by the immigrants themselves. .... In 1900 there were
over 1,000 societies in New York...
Any idea how to identify institutions that may have records related to a
particular family or community,"

Jeff, i wouldbegin with the Jewish Communal Register of 1918. This was
a survey of communal organizations in New York City and it has been
digitized on Google Books. For landsmanshaftenand other societies it
contains lists of officers, names and addresses. find it at The
Jewish Communal Register of New York City, 1917-1918...
https://books.google.com/books?id=islKAQAAMAAJ

For the orphanages...first try the census as the inmates at the Jewish
Orphanages were included. Note that many inmates were there
temporarily when their parents could not care for them. Second option
is the query at the Center for Jewish History which has listings from
some of the major orphanages...at
http://genealogy.cjh.org/familycollections.php
Last option is the HOH Jewish Orphanage Site that is no longer
online...but do try the the wayback machine which archived many of the
orphanage pages; you'll find the archive at https://archive.org/
Or, you could consider our New York Genealogy Class in August
(www.jewishgen.org/education)

happy hunting
Phyllis Kramer, New York City, Palm Beach Gardens, Fla
V.P.Education, JewishGen Inc: www.JewishGen.org/education
Researching (all Galicia) ...KRAMER, BEIM >from Jasienica Rosielna
...SCHEINER, KANDEL >from Strzyzow & Dubiecko ...LINDNER, EICHEL from
Rohatyn, Burstyn ...STECHER, TRACHMAN >from Nowy Zmigrod, Dukla
family web site: KehilaLinks.JewishGen.org/Krosno/Kramer.htm