How many public school buildings in the US were of the one-room variety?

At the peak of one-room schoolhouses in the early 20th century, there were approximately 200,000 such buildings in the United States. These schools served rural communities and were designed to accommodate multiple grades in a single classroom. Over time, the number of one-room schools has significantly decreased due to urbanization and the consolidation of school districts. Today, only a few hundred one-room schoolhouses remain in use.