Nancy wrote: My grandfather, August Alfred Siegmund, was born in New Jersey in 1889. I was surprised to find him listed in the 1900 census at the Society for Relief of Half Orphans and Destitute Children in New York City because I never knew he was orphaned. He remained in the NYC area and married there in 1913. I assume records were kept when a child was placed in an orphanage - where would I find those records?
MY ANSWER: Hi Nancy. Congratulations on your new find! Half orphans were those who had one parent still alive but that parent could not care for them. So it seems likely your grandfather was not a true orphan (meaning both parents dead)
Yes, the orphanages kept records - often good records, so you can have a look in the FHC catalogue to see what is filmed
There are some orphan records online and also a bit of history on New York orphanages which might interest you.