According to the APA Style Blog (published by the APA), the basic website reference should be in this format:

Author, A. (date). Title of document [Format description]. Retrieved from https://URL

In text: (Author, year)

However, your example will require a couple adjustments: 

1. The Blog adds, "That format description in brackets is used only when the format is something out of the ordinary, such as a blog post or lecture notes; otherwise, it's not necessary." So you do not need to enter a format description for the ZipDataMaps reference.
2. Also, the Blog advises that when no author is given, as in the case of your source, you leave the author field blank, and the title moves to the author position.

So your reference would look like this:

Baltimore Neighborhood: McCulloh Homes. (2018). Retrieved from https://www.zipdatamaps.com/nh-baltimore-neighborhood-mcculloh-homes

And in-text citation would look like this:

("Baltimore Neighborhood: McCulloh Homes," 2018).
 

For additional guidance, see this entry in the APA Style Blog:

Lee, C. (2010, November 18). How to Cite Something You Found on a Website in APA Style. [Blog post]. Retrieved from https://blog.apastyle.org/apastyle/2010/11/how-to-cite-something-you-found-on-a-website-in-apa-style.html