On the eastern edge of the parish in the town of Mid Calder is Kirk of Calder. There has been some form of church on the site since the 12th Century. The church that is there now was built in 1541 by Lord Torphichen, Sir Patrick Sandilands, on land next to Calder House. The church has been extended across the years but retains much of the original 1541 structure and features.
In 1643 the West Kirk of Calder was built on the western moorland. The village of West Calder then grew up around the kirk. The two kirks remained under the same minister until 1647. A new West Kirk was built at West Calder in 1880 but the ruin of the old West Kirk remains in the centre of the village.
The kirk elders were respectable, well to do local men who were elected to the kirk session.
At Calder in 1644 and 1645 eight men were ordained as elders:
Gavin Anderson; John Ker; John Stevenson of Herdmanshields {Hermand}; John Purdie in Hairtburnhead {Harburnhead}; James Wallas in Cleutheid {Cleughheid, vanished now but was near West Calder Post Office at the top of Cleuch Brae}; John Hamilton of Grange; Mr James Kynloche of Alderstoun; and Gawaine Vernor in Dedridge.
The kirk bailie was another important and powerful member of the community. Appointed by the session, he was responsible for local judiciary matters in a similar role to that of magistrate. In 1640s the bailie of Calder was another member of the Sandilands family, James Sandilands of Muirhousedykes {now Loganlea, Dykes, by Addiewell}
The kirk session was responsible for administration of the parish and minor judicial issues and the session clerk kept detailed records of the Kirk session meetings. These session records have survived and they show payments to the poor, for running of the school, or for repairs or services to the kirk and session itself. They also record implementation of local laws and the accusations, trials, and punishment of parishioners.