Help searching Duluth addresses for old businesses

There is no easy online way of getting the info you are looking for, as far as I know, but it can be done the old fashioned way at the Duluth Public Library using the Polk City Directory for any given year. Ask the reference librarian or just enter the room on the second floor at the top of the stairs and look to your right. There is an island shelf with rows of city directories. Older versions are on microfilm.

Wow, does that mean someone ran to the library to answer questions of PDD? That's pretty nice of them if so! Speaking of which, does anyone know if the online options at the library are any good? I noticed that if you have library card they'll offer some access to things.

Update: the Polk City Directories are on Ancestry.com. Are there and tips in searching since I can only browse it and not search by address?

Sanborn Fire Insurance maps are a great resource. The Library of Congress has 6,000 sheets online, but it looks Minnesota isn't listed.

Minnesota Reflections, a digital clearinghouse of scanned historic info from various museums and archives throughout Minnesota, is worth checking out, as are the digital archives available through Minnesota Historical Society.  Both the Iron Range Research Center (Formerly Ironworld) and Northeast Minnesota Historical Center Collections (@UMD) have provided content for MN Reflections. Try to find the Sanborn maps through them. MHS digital collection has great historic photos of Duluth digitized and searchable.

I use the online directories on Ancestry.com quite a bit, and you get better at knowing what you're looking for and how to get there with experience. Their search function, as you say, isn't that great in that regard, so it often requires paging through, or guessing what section the thing you're looking for will be in. It doesn't help that Polk had a habit of changing how they organized things every few years. 

Honestly, using them in person is often faster. The UMD library has longer hours than the DPL.

If you're looking for what's at a specific address, you're right: It's more difficult. Finding the name of the building that was there involves detective work at times, involving Sanborn maps, or sometimes Polk had a list called "public buildings" (which meant any office building). It doesn't help that older Duluth buildings didn't always use clear addresses or they sometimes changed. 

The best resource is going to the public library with the address you're interested in and visiting with a librarian on the second floor. Make an appointment with Maryanne Norton. She knows just about everything, or at least how to find out.

You can search the Polks by address at the library. Just takes a bit of guessing to nail down what you're looking for. And MaryAnne recently showed me the  Sanborn maps. It's worth it just to see them. I think it's cool to physically go down there, where the ref people are helpful as all get out. You find stuff you'd never get online, like their subject files full of all kinds of ephemera.

Rootsweb has a 1949 Duluth telephone directory that might be helpful.