One of the Royal Parks of London. A place that's occasionally mentioned in the story.

The Crystal Palace was a cast iron and plate glass structure built in London to house the Great Exhibition of 1851. The Crystal Palace for many years was the site of shows, exhibitions, concerts, soccer games, and other entertainments. In 1936, it was destroyed by fire and the towers that survived were finally demolished in 1941 because they was conspiracy that German bombers would attack it. (Chapter 19)

Mary receives a letter by a young girl, sent from Portman Square. Portman square was established on land that was once owned by Henry William Portman. At one time there was an infantry barracks there which has since been demolished.

(https://en.wikipedia.org/wiki/Portman_Square)

After David finishes school in Canterbury with Dr. Strong, Aunt Betsey asks him what it is that he wants to do with is life. With David being unsure of the answer, Betsey suggests that David take up an apprenticeship to become a proctor. Doctors' Commons is where David takes up his apprenticeship under Mr. Spenlow and Mr. Jorkins. During his apprenticeship, David enjoys a newfound sense of freedom living on his own in London. His aunt had an apartment arranged for him to stay in while he learned how to become a proctor. She also hired Mrs. Crupp to cook for David.

"When did you see her, Mary?" she asked presently. "You seemed to know her when we stopped at that bed."

Home to the royal family, at the time the novella was published Queen Victoria and her husband Prince Albert were the ruling family.