The first pic appears to be White Oak. Second is too far away to tell. Third is definitely Red Oak as evidenced by short medullary rays. The final pic appears to be White Oak but isn't really detailed enough to say for sure. If you cut a slice off one of the ends in pic 4 you can see if the soft grain is open which is an indicator for Red Oak.

The original floors are white oak. The new add-on floors are red oak.

Oh boy. Some of the previous owners were real dopes. So they laid red oak in the kitchen when the original was white. Hmm..

@G & S Floor Service - This is the upstairs hallway.. seems like some rays are shorter than others.. would these be white or a mix?

You can see the shorter boards on the left..

And here’s a photo on the main floor (original oak) that isn’t stained because it was underneath the massive colonial fireplace I deconstructed.

White Oak, White Oak and White Oak. Look at the third picture you posted originally. See the short rays parallel to the board direction. Those are the surface exposure of medullary rays. The short length tells you it's Red Oak. Contrast those with the ones on the boards where you removed the fireplace which are clearly longer, telling you that's White Oak.

Also, Red Oak is more uniform in color from board to board and within each board. While Oak has darker heartwood and lighter sapwood and will yield more boards with distinct stripes of dark and light, like your two next to last photos.

@Timothy Winzell That makes sense. Thank you! The particular areas in my kitchen I took photos of had been underneath cabinets and the fridge. It also looks like that area had been cut and boards possibly replaced. I'm hoping that's only where the red oak is and perhaps the rest of my kitchen is white oak. Hopefully!

@Timothy Winzell We had the doorway leading into our kitchen widened about a foot so this is a better photo of boards running through my kitchen. Fingers crossed it's white so it'll be easier to match the dining room.

@Timothy Winzell Thank you so much for your help! I saw a few photos of 1920s white oak freshly sanded and they're beautiful so this is awesome news.

Hey guys! Just wanted to let you all know you were spot on, of course. Kitchen is red oak, main floors and upstairs are white.. and naturally all patched in oak amongst the white is red.

It’s so beautiful I may just do Bona NaturalSeal followed by Traffic HD. My floor guy didn’t bring any Bona products with him to test out so I’m hoping you all have some advice to offer for the red oak in the kitchen. (Planning on emailing him tonight to confirm he’s bringing NaturalSeal and Traffic HD with him tomorrow).

What would be the best product to use on the red oak to try and match as closely as possible to my natural white oak? I know it won’t be perfect and that’s fine. Just hoping to give him a heads up since he only brought 5 Duraseal stains with him today and all but 1 were med-dark.