The list, released on Wednesday, also includes Russia, Syria and North Korea.
Explaining the decision to include the US on the list for the first time, ICC said: "Throughout the US, current events and shifting perceptions are causing conflicts between Christian beliefs and public sentiment.
ICC Hall of Shame List 2016
- USA
- Mexico
- Iraq
- Syria
- Egypt
- Russia
- India
- Pakistan
- North Korea
- China
- Saudi Arabia
- Nigeria
"This cultural shift affects Christian businesses, organisations and individuals through legal action, free speech infringement, public expressions of faith, and employment.
"While there is no comparison between the life of a Christian in the US with persecuted believers overseas, ICC sees these worrying trends as an alarming indication of a decline in religious liberty in the United States."
The American-based watchdog points to the case of a Christian football coach suspended for praying on the field and a Christian business owners forced to pay a $135,000 fine for declining to bake a cake for a same-sex wedding as examples of the what they claim is the diminishment of religious freedom.
The 15-page report also highlighted the plight of Christians in other parts of the world including the ongoing persecution of Christians by Boko Haram in Nigeria and the crack down on Christianity in China.
ICC has been helping persecuted Christians worldwide since 1995.