Your recessed medicine cabinet probably isn’t right up against your drywall so you can probably get two monkey hooks to hang a mirror. Have you put the countertop/sink on the vanity yet? I’m concerned you don’t have enough space for the overhang on the left hand side of the vanity.

@Liz H Thank you for your reply. Unfortunately in my case, the recessed medicine cabinet behind my other bathroom is in fact right up against my drywall, so I can't use monkey hooks. Regarding my counter top, the contractor didn't take that into account when installing vanity. He is planning on moving it away from the wall a bit. Do you have any mirror suggestions that would look good with my vanity/side wall niche/size restrictions? Thank you!

Is the other bathroom your master bath? Can you move the medicine cabinet to the side wall? If not, your only option would be glue if the medicine cabinet is flush with the drywall, unless it’s not super tall. How tall is the cabinet?

This mirror is suspended by hardware that is mounted above the mirror.

Minimalist Mirror

Another possible but too large probably:

But same concept would work with other mirrors and be at home in an 1880 house...

West Elm Modern Hanging Oversized Mirror

Or use inexpensive mirror clips and hang a frameless mirror:

https://www.lowes.com/pd/Style-Selections-Metal-Mirror-Clips/1056919

@Liz H - I live in a side-by-side duplex; the other side is owned by another person. Their bathroom is a mirror image of mine. But they lucked out with getting a recessed medicine cabinet! Their vanity is taller than mine and their medicine cabinet is tall. I can't even screw holes in my wall until it's above their mirror, which would make my mirror too big/high. Ugh, this is so complicated!

@kandrewspa Thank you! Maybe I will like the floor better once the bathroom is completed.

@ci_lantro Thank you for your reply and suggestions! I like the round hanging mirror. Not sure what kind of light would work with that though. I need overhead vanity light since there is no room for side sconces.

I like the rounded rectangle mirror form pottery barn.

I also like the way the floor turned out, I wouldn't darke it just yet, live with it a little and see how you like it.

I can't tell from the photo how different the trim is from the wall but I wouldn't paint the niche the wall color. I would keep it white or trim color. When it's the same color it looks to me like someone was repainting the room and was too lazy to switch colors.

Post pics when you're done, would live to see!

I guess they had no fire codes in 1880. :) I absolutely know it’s not to the time period but you can also get an LED mirror to take the place of your light. I’ve done it in a couple of my bathrooms and it looks great— you may have to move the electrical down a bit— as far as possible to their cabinet height. None of the LED mirrors look Victorian but with the other ‘older’ features in the room, it may not be too, too bad.

This is a shared wall with another bathroom that has a recessed medicine cabinet that is 24” wide (in the exact spot where my mirror needs to be).

Recessed of course fits between studs. And the framing in the wall may have been altered for it to fit. What you need to know is the stud distance center to center.

Or the exact size of the cavity between the studs. Because what is billed as a 24" medicine cabinet may be sized to fit in the recess between 24" OC framing. The actual space between the studs would be approximately 22.5"

If that is the case, then a 24" surface mount medicine cabinet would work.

Signature Hardware Trossman 24" x 36" Framed 1 Door Medicine Cabinet

But they lucked out with getting a recessed medicine cabinet!

Yes, they did. But you can have a surface mount medicine cabinet which would be very much in tune with your old house.

Two of my vintage ones:

If all else failed, I would make a custom vintage style one.

Would need to keep in mind how far the sconces project light from the wall & possibly add mounting blocks behind them to get them farther away from the wall.

@ci_lantro I considered surface mount but was worried about hitting my head when washing my face. So scrapped that idea. Do you ever find that to be an issue? Also my bathroom is so small and I was worried about closing it in. But maybe it's not that big of an issue??

I started thinking last night that instead of the recessed niche that I was planning on getting for the side wall, I should just get a recessed medicine cabinet instead. Would be more practical. and I have the space for it between my studs. I just don't like the look of a mirror on the side wall and would need to figure out how to change that out with a wood door or opaque glass.

I love your vintage cabinets!

I like the Pottery Barn pivot mirror. I had the Kensington pivot mirror in my previous home and really loved how it looked. I think the one you've linked would look great with your setup. Your vanity and flooring are already very pretty.

@pricklypearcactus Thank you for your comment! Do you think that mirror would look ok in chrome with the color of my vanity? One of the dilemmas I am having is that I was planning on chrome fixtures (already have purchased the faucet), but now that I see the vanity in person, I'm feeling like chrome is not going to compliment the color of the vanity. However, I am terrible at visualizing all this so so maybe it will be fine?

Can't answer the head bonking question because neither of those cabinets are over a sink. But I would think it wouldn't be a problem because faucets are going to cause you to keep your head well away from the wall, won't they? If not, after you bang your head a couple of times, you will adjust. :-)

I do have side wall cabinets in all three bathrooms though. Didn't have any other option because one vanity is along an exterior wall in Wisconsin. No recesses in exterior walls!

Plumbing, plumbing vents and HVAC prevented recessing above the vanities in the other two bathrooms.

Because none of my bathrooms have a window, I did use mirror on the side wall cabinets. Mirror amplifying the lighting. But there is no reason that you need to do that. Perhaps you would like the idea better is you used a simple painted or stained Shaker door instead of mirror?