Interest rates can differ from city to city and from state to state. Although national mortgage rates follow U.S. bond rates, local factors can play a part. For example, in areas with high unemployment, banks might lower mortgage rates to try to get business.
It’s all about money
If the economy is good and there is great demand for homes, lenders might raise interest rates because they can and still get business. Smaller loans, however, might come with a higher interest rate than larger loans because it costs lenders just as much to process a big loan as a small one, so they might charge more for a smaller loan, which they don’t make as much money on.