 The Walnut Hill neighborhood is sandwiched between the city's downtown and Walnut Hill Park, which was originally built out as a water supply reservoir, but was converted into a public park in the 1860s.The area now contains an architecturally diverse collection of housing, built between about 1840 and 1930.Most of the houses are of wood frame construction, and are generally of similar size and scale, set on similarly sized lots with uniform setbacks, giving the area a cohesive feel despite its architectural diversity.