The light switch is throwing me off. How high up will the backsplash come from the counter?

@Ellen S That telephone jack? I know, I should've gotten rid of it :) But cell reception is terrible in our neighborhood so I figured it might be good to keep as a backup. The backsplash will go all the way up to the cabinets.

Makes sense!

Since it will go up to the cabinets, I think having it extend beyond the line of cabinets will look strange.

Either way you go, I’d put something on the end of the counter that is tall enough to cover the strange open space, like a tall vase or basket.

@Ellen S Good idea. I have a plant that might do just the trick!

Extend to end of counter and get hard wire connection changed. Not a big deal. It will look much better and you will need a pencil trim or thin Schluter trim edge for edges beyond cabinet. Not a big deal either.

@Flo Mangan thanks for your suggestion and for sharing photos!

Keep it in line with the upper cabinets. Having the tile extend past them just looks odd.

Do NOT extend it past the uppers. The rule of thumb is to stop at the uppers otherwise you get the odd look of tile floating by itself. There are some occasions that it makes sense to extend tile out but in your case it should end at the uppers