Unfortunately I don't have any better pictures at the moment...

It is currently being used as a laundry room. The walls are covered with beadboard looking wood which is original, and it has a couple of shelves and a mirror which may be original. I suspect the door and window in the foreground of the first picture have been added later on. The second picture shows where I suspect the original door was. The third picture is a crude but pretty accurate drawing of what I believe the original layout of my house was before it was added onto in the late 20s early 30s... The room is labeled with a question mark.

Pantry with possible door to the exterior for ice delivery?

-Mike

It was most likely a utility porch. Almost every bungalow had one, typically right off of the kitchen. They were often screened in, although in northern climates having a utility porch that was glazed with glass windows was not uncommon. They usually had beadboard ceilings, and either beadboard or siding covering the walls. This is where tools, mops, etc. were kept.

Often times there were milk doors leading from these porches directly into the kitchen. In areas which had alleys the deliveries from the milk man, ice man, etc. were made from the alley side of the house. In areas which did not have alleys, these delivery doors are often located on the side of the house, which often had a smaller service sidewalk leading to them from the street.

I have one. It was called a "breakfast room" when we bought the house. The previous owner (she was the original owner) used it for a sewing room. They had also installed a tiny 2-piece bathroom in there during the 80s when they were too elderly to walk upstairs every time.

We put our laundry room in there because we couldn't fit the new style machines down the stairwell into the basement.

Mike and westvillager are both correct. My brother's 1912 bungalow still had his utility porch intact with the little 2 piece bathroom in the corner with a separate door. It was essentially a back porch that had been enclosed over time when refrigeration came and the ice man didn't deliver anymore. It had a place that had been filled in on the driveway side where the metal-lined boxes held the ice. There were also screen-backed square openings high and low for (what I was told) cooling pies and storing cheese. The utility porch/room had the bead board ceiling and walls. We can see in your third picture that the siding doesn't align. Basically anytime you see a vertical trim board like that it can indicate that something's been filled in. Perhaps it was more open at the wall base at one time. Our utility porch got enclosed in the late 50's and brought into the kitchen as an eating nook. Now I'm designing a new utility space to replace the one lost to the interior. They sure are useful spaces, kind of like a mudroom/energy lock. Great for shoes and wet dogs.

Absolutely a "mud room". I have the same in my home.