The synagogue is covered with a shingled mansard roof. The log walls, without weather-boarding, were reinforced by vertical posts and metal bolts. The building was lit by segment head windows. Six of the windows looked into the prayer hall (two on each of its south-western, south-eastern, and north-eastern sides), two other smaller windows of similar shape looked into the women’s gallery on southwest and northeast.
The women's gallery spanned the winter prayer room, vestibule, and the staircase, and jutted out into the prayer hall on its north-western side. The projection of the women’s gallery into the prayer hall was supported by two wooden Doric columns in the rear of the prayer hall. The whole interior space was spanned with a wooden cove dome, fitted into the roof construction. The dome and partition of the women’s gallery were painted in 1895 by an unknown local Jewish artist, who later emigrated to the United States (Lemchenas, “Pakruojo medinė sinagoga,” p. 101).
The painted subjects included trees inhabited by birds and animals (such as stork bringing a worm for its nestlings, and a peacock), a deer, a lion inscribed with a verse,
"ארי שאג מי לא ירא"
(“The lion hath roared, who will not fear,” Amos 3:8, Fig. 11), an open Torah ark containing Torah scrolls and with two Torah scrolls attached to the top, a train arriving at a two-story building between two trees, a table with books, vases of flowers, and at the center of the dome there was a Leviathan, holding its tail in its jaws, circling a town house.
On the partition of the women’s gallery appeared animals mentioned in the Mishna Avot 5:20: “Be strong as the leopard, swift as the eagle, fleet as the gazelle, and brave as the lion to do the will of thy Father which is in heaven.” There is a fifth animal, a camel, painted next to the image of the lion.