"Wat Prang", as it's called by the locals, dates from the early 13th century, making it one of the oldest temples in the Si Satchanalai area. The large corn-cob prang is a strong clue that the temple was started by the Khmers, but it was expanded and modified all through the Sukhothai and Ayutthaya periods. This is perhaps the best place to start a tour of Si Satchanalai.
The temple is arranged in a linear plan running from east to west. At the eastern end is the ordination hall, a modern building built on the foundations of a much older structure. You can see the old foundations stones at the rear of the building, opposite the gate to the central complex dominated by the soaring prang.
The wall around the central complex is a rather unusual construction. It is made of large stone cylinders set on the ground close together, and topped by more slabs of stone running horizontally. The eastern gate to the central complex is topped with a massive stone lintel crowned by a four-faced bust of Brahma. You'll most likely need to duck down to make it through the gate.
Inside the main complex, there is the large central building, dominated by the prang, flanked by two smaller temples. The one to the right enshrines a Buddha image sitting on a coiled serpent, similar to the one at Wat Chedi Jet Taeo.
Inside the main prayer hall is a large seated Buddha image. While impressive, the real gem is a walking Buddha to the left of the main image. To the right of the altar is a standing Buddha which is sunk into the platform, perhaps a sign that the prayer hall was added to the prang later, or modified at some point in time.
Behind the prayer hall to the right are stairs leading up to a chamber midway up the side of the prang. The chamber is protected by two massive wooden doors. Inside is a large lotus-bud shaped linga. Dawn Rooney says the chamber is empty, so maybe this idol is a recently installed reproduction.
A gate in the west wall of the main complex leads to a second complex of temples and shrines. Immediately in from of you as you pass through (or under, really) the gate is the ruins of a large stupa (Phra That Mutao). Only the base and the lower part of the bell remains.
Behind the chedi to the left is a mondop enclosing the Phra Attharot Buddha image. It is similar to the structures found at Wat Mahathat in Sukhothai.
Next to Phra Attharot are the ruins of another large prayer hall, called Phra Song Phi Nong, which means, roughly, "two brother monks". It refers to the two seated Buddha images which sit on the two-tier altar. The ruins are shaded by a large tree, which makes it rather photogenic if you catch it at the right time of day, which I didn't.
Admission to the temple is 20 Baht (0.52 USD).