Books with: Girl goes to work in mysterious house

[Sally]

Verity by Colleen Hoover could kind of fall under that category. Psychological thriller with some romance.

[Jon]

I'm only a quarter in so I'm not sure about romance, but Riley Sager's Home Before Dark has a female MC renovating a mysterious house.

[...cats?]

The Turn of the Key and the original, The Turn of the Screw
The Little Stranger
The Family Plot

[Crystal]

Brightly Burning: This is set in a more technologically advanced universe where people live in space. But it's really solid! (it's a YA retelling of Jane Eyre in space)

The main character finds work as a governess in an expensive private cruiser - the owner of the space cruiser is mysterious and there's definitely romance here!

It has sci-fi elements here but it's a very light version of sci-fi. The main focus of the book is on the characters and plot.

[Lobstergirl, au gratin]

Do you mean young girl, or an adult woman?

[Kris]

Molly, would you say the genres you're looking for are: adult (not teen) mystery, some romance?

[Pamela]

Jane Eyre by Charlotte Bronte Jane Eyre

[Scott]

This House is Haunted

[Nora]

The Animals at Lockwood Manor

[Rainbowheart]

Murkmere

[Rainbowheart]

This House Is Haunted