Nakorn Chum was a much smaller town on the west bank of the Ping River. It appears to pre-date Kampaeng Phet, at least in the historical record. The laterite stone that much of Kampaeng Phet's monuments are made of is less available on the west bank, so most of the temples were made of brick. Nakorn Chum had walls as well, but they were simple earthen ramparts for the most part, and little of them remains aside from a few forts that were made of stone.
The city of Nakorn Chum was north of the modern highway which cuts through Kampaeng Phet. This is where Wat Phra Baromathat, which appears to have been the principle temple of the city, is located. The city's Aranyik forest temple area was located south of the highway, in what is now mostly rice fields. There are perhaps half a dozen ruined temples in the area. The two that are most worth a visit are Wat Chedi Klang Thung and Wat Nong Langka.
The main pagoda at Wat Chedi Klang Thung The only remaining structure at Wat Chedi Klang Thung is a pagoda showing the classic fine lines of the Sukhothai style. It was probably built in the later half of the fourteenth century, when Sukhothai was still the dominant power. You can just make out the base of the chapel on the eastern side of the pagoda, and the whole thing was once surrounded by a moat, which has gone a bit swampy in places, at least in the wet season when I was there.
The overgrown pagoda of Wat Nong Langka Wat Nong Langka is one of the largest remaining temple ruins of Nakorn Chum's own Aranyik area of forest retreat temples. It has a large bell-shaped pagoda in the Sukhothai style. The base of the pagoda has several niches for Buddha images, and there are the remains of many chapels and shrines around the tower. The entire thing was surrounded by a moat which still fills with water in the rainy season.
The gold-painted pagoda of Wat Phra Baromathat Wat Phra Baromathat is one of the oldest temples in the Kampaeng Phet area, and one of the few ancient monasteries that is still active. It probably dates from the mid-fourteenth century, when the old city of Nakorn Chum on the west bank of the Ping River was more important than Kampaeng Phet across the river. The pagoda (chedi) was probably originally similar to the one at nearby Wat Chedi Klang Thung, but it was restored and rebuilt in a very Burmese style late in the nineteenth century by a Burmese teak trader.