I first read about “thin places” in some evangelical writings several years ago and was surprised this concept had made its way into the church. Thin places refer to geographic locations that supposedly possess a sacred quality one can sense or feel. I was familiar with this idea from experience as a New Ager. However, “thin places” such as Iona, Scotland are presented as Christian:
“For over 25 years, I have wanted to return to Oban and visit Iona, one of Christianity’s great holy sites where pilgrims flock from around the world to pray and experience what the Celts call “a thin place,” where heaven and earth seem to touch. George Macleod, founder of the Iona Community, wrote that Iona is “a thin place where only tissue paper separates the material from the spiritual.” From “The Thin Place of Iona” by Marek Zabriskie. 
So is there such a thing as a “thin place,” and where does it come from?

Thin Places Are Pagan

Places and spaces can be sacred or have a “special energy” in the New Age understanding, an example of which are the so-called vortices of energy believed to exist at certain geographical points.
These “thin” places are allegedly where the separation between two worlds is at its thinnest, such as between the natural and supernatural, earth and heaven, the living and the dead, the past and the present, or between material matter and a spiritual state where one can connect with God or the Divine.
Interest in and acceptance of such mystical concepts as a thin place are increasing in the church. For example:
Associated with Celtic Christianity, thin places are certain landscapes where the veil between heaven and earth is said to grow diaphanous, thresholds that, once crossed, usher the visitor into a heightened awareness of God’s presence. What follows is a lifting of weight, a sudden illumination. From “Geoff Dyer and ‘Thin Places'” by Fred Bahnson
So where does this idea for a “veil between heaven and earth” come from? Although often attributed to Celtic Christianity, this concept is much older and is, in fact, actually pagan.
We know that sects of the pre-Christian Irish believed there was another world – and Underworld where a parallel civilization (often linked to enchantments) lived. They believed there were openings where the inhabitants of the other world came and went between worlds – thin places. Legends of fairy forts or nodes where passage between worlds was possible were known as thin places or enchanted places….<snip>…..The thin places concept was a part of the pre-Christian or pagan charism and these beliefs or sensitivities – existed prior to the Celts. The concept is rejected by many of the present day Christian communities, often being linked to “new age” heathenism. (From an article by Samir Selmanovic refuting Richard Rohr’s claim that “thin places” come from Celtic Christianity, that is no longer online)
“Thin places” are similar to the occult idea of the “veil between life and death,” and similar to the pagan concept of a “veil between this world and the next.” There is no physical, factual, or biblical basis for this notion. The only reasonable conclusion is that this view of a thin place seeped from paganism into Celtic Christianity.
The veil is said to “grow diaphanous” so that one can actually “cross over” somehow into God’s presence. This would imply that in certain places one cannot cross into God’s presence due to the lack of “thinness” in that place. On what basis is that even logical? Must one be in a “thin” place to be in God’s presence or to get spiritual blessings? This can become a worship of a physical place.

 The True Veil

I view the so-called “thin place” and the “veil” of thin places is a counterfeit to another veil.
Prior to Christ’s atonement on the cross, those who believed in the true God relied on the high priest, who entered the Holy of Holies in the Tabernacle (and later the Temple) once a year, to go before God’s presence and ask for forgiveness of his sins and the people’s sins. This was the solemn Day of Atonement.
The Holy of Holies was separated from the rest of the Tabernacle/Temple by a massive veil or curtain about 60 feet in height, 30 feet in width, and, according to talmudic sources, about 4 inches thick (but this is not in Scripture so we cannot be sure).
But at the moment of Jesus’ death on the cross, this huge, heavy veil tore from top to bottom, an act that could not have resulted from anyone but God.
 “And the veil of the temple was torn in two from top to bottom.” Mark 15:38 (Also in Matthew and Luke)
The book of Hebrews explains what this means:
 “…since we have boldness to enter the sanctuary through the blood of Jesus, by a new and living way He has opened for us through the curtain (that is, His flesh), and since we have a great high priest over the house of God, let us draw near with a true heart in full assurance of faith, our hearts sprinkled clean from an evil conscience and our bodies washed in pure water.” Hebrews 10:19-22
The curtain or veil referred to here is the flesh of Christ, the High Priest, torn with suffering and death on behalf of sinners, offering forgiveness to all who believe. Christ atoned for sins on the cross, thus ending the need for the yearly Day of Atonement.

 Science, the Guardian Deity, and Thin Places

This part of the article at first sounds as though a scientific basis will be given for the “thin places.”
I recently met an Irish tree scientist, a famous biochemist who studies the effects of forest aerosols on human health. Her scientific credentials are impeccable. When I asked her about thin places, she told me about Gougane Barra, an island on a small lake where St. Finbarr the monk built an oratory in the 6th century, a place she said possessed numinous qualities. “There’s a wall of prayer surrounding that place,” she told me. I would feel it when I approached. The genius loci, the spirit of the place, would be palpable. From Bahnsen’s article
This woman’s credentials may be “impeccable” but apparently play no part in her belief that the island has “numinous qualities,” and that somehow a “wall of prayer” surrounds it. Moreover, what science is there in a so-called “spirit of a place?” What is a “genius loci?”
Genius loci is the Latin for the spirit or guardian deity of a place and is a phrase that has been adopted in English and into other languages. From a website by Edward Relph
A “guardian deity” fits into the ancient pagan beliefs about gods being located within certain boundaries. They could not travel and were thought to be effective only in their area. This is why God’s statement to Jacob in Genesis 28:15 that he would be with Jacob wherever he went, was so astounding at the time. The pagan gods could not travel; their images had to be carried from place to place.
“Behold, I am with you and will keep you wherever you go, and will bring you back to this land; for I will not leave you until I have done what I have promised you.”

Pagan Veils

To seek out and believe in such “thin places” does not bring honor to God or to Jesus but rather to the location. It is creation-oriented, not Creator-oriented.
Some may point to special places in the Bible such as the Burning Bush where Moses encountered Yahweh, or where Jacob had the vision of the ladder/stairway from heaven. But in those cases, actual events were taking place that involved an act of God, and it was for a limited time. These were revelations from God, not thin places.
The geographic location itself was only special because of what God was revealing. If we could go to those exact places now, there would be nothing special about them except that they serve as a reminder of a past unique event connected to a revelation from God.
Focusing on an alleged thin place can easily distract from God and become a substitute for seeking God himself and obscure the incomparable truth that God sent Jesus to reconcile us to God. Rather than a place where a pagan veil is supposedly thinnest between earth and heaven, or death and life, the real veil between God and man was done away with via Christ’s death.
 “…but whenever a person turns to the Lord, the veil is taken away.” 2 Corinthians 3:16
This refers to the veil over Moses’ face after he came down from Mt. Sinai and is used here to refer to the removal of spiritual blindness when one turns to Christ.
Any other veil only hides the truth of the real veil. So if you have not trusted in the Son of God, Jesus Christ, realize that the veil is torn and you can be forgiven of sins and be reconciled to God. Any veil is removed when you turn to Christ. No need to seek thin places or contend with veils.
“For Christ did not enter a man-made sanctuary that was only a copy of the true one; he entered heaven itself, now to appear for us in God’s presence. Nor did he enter heaven to offer himself again and again, the way the high priest enters the Most Holy Place every year with blood that is not his own. …But now he has appeared once for all at the end of the ages to do away with sin by the sacrifice of himself.” (Hebrews 9:24-26)
 “But God had foretold through all his prophets that his Christ must suffer and this was how his words came true. Now you must repent and turn to God so that your sins may be wiped out, that time after time your souls may know the refreshment that comes from the presence of God.” Acts 3:18, 19 (Phillips Translation)
Further Information on the Veil