The Lenox family is from Scotland.  Edith goes to Scotland for a wedding tour.  This picture is of a park where Margaret meets Bessie and Nicholas Higgins. Mr. Thornton also has a scene in this park. This park is located in Edinburgh, Scotland. 

This is where the battle of Tchernaya took place on August 16th, 1855. Mrs. Seacole narrates her experiences trying to help men wounded on the field in Chapter 16, and it is horrific. Literally called the Black River, it's a common name for rivers and was a battle site during the Crimean War. Despite having vastly more men than the allies, the Russians lost spectacularly. 

Mary Barton works for Mrs. Simmond as a seamstress. While the shop is reportedly well off, Mary is paid close to nothing and worked to the bone: