How do I find out what bank holds the mortgage on a house I want to buy.. it is about to go to foreclosure?

Check with the county clerk's office. A mortgage is usually filed as a lien against the property. Foreclosues may also be filed with the clerk.

You will need to know the owner's name so that you can locate any mortgage(s), as Scott says, filed as a lien in the county's deed records. Foreclosures are generally advertised in the county's legal newspaper for four weeks prior to auction.

You will need to know the owner's name so that you can locate any mortgage(s),

Not necessairly. Liens may be recorded against the property so can be found by checking the property.

Not necessairly. Liens may be recorded against the property so can be found by checking the property.
Where would you begin to look if you don't have the owner's name?

Property deeds are generally filed by location, not owner. To find a deed, one would need the address or the section, block, lot etc. Generally just the name will do no good.

Scott, so you and other readers will know, in my neck of the woods, anyway, property is indexed by name; there are two indexes: Grantee and Grantor. This type system makes research accessible.

You can do property searches at the recorder of deed by address only. At least in every state I have ever bought property ( and that is quite a few )
You go in with the address and can look up who the deeded owner is and who has any mortgage.

BUT>>> if it is not foreclosed yet ( and how do you do it is going to be foreclosed if you don't know the owner)

But until it is foreclosed you will have to buy it from the owner, not the bank, since the bank does not own it until it is foreclosed

I'm sure that some counties do allow name searches. But the vast majority that I'm aware index properties by location. If a name search is provided, its in addition. Most of the time, people don't search for property that someone owns, but rather the owner of a property. In fact, it might be considered an invasion of privacy to allow someone to just look up all the properties someone owns. A few years ago, as part of its re-assessment program, my county put up all the assessment info on its web site. They inclouded owner info aqnd the ability to search by owner. There was a large hue and cry complaining about the loss of privacy and the names were removed.

Most will have a cross reference my name, and/or tax records that cross reference to address but to my knowledge most areas will always have the address search and many others will have other methods in addition to address search