The majority of Americans believe that faith in God is an important component of being a true American, but that the US is not a Christian nation, a new study has found.

Data compiled by the Public Religion Research Institute found that 69 per cent of Americans agreed with the statement that a belief in God is an "important part of being truly American". This view was more popular among older people, held by 77 per cent of seniors in comparison to 52 per cent of young adults.

The view was more widely held among Republicans (81 per cent) than Democrats (63 per cent).

More than half (53 per cent) of those asked said that being a Christian is an important part of being truly American, a figure that rose to 75 per cent of white evangelical Protestants and 55 per cent of Catholics. Two-thirds of those who don't identify with any religion said that Christian identity is not important.

However, most Americans do not believe that America is a Christian nation. Around 59 per cent said that it isn't, though 45 per cent agreed that it once was. Just 35 per cent said that it is currently a Christian nation, perhaps pointing to the decline of the religion across the US.

Despite a fall in the number of those who profess a Christian faith, a recent poll by LifeWay Research found that more than half of Americans believe God has a special relationship with the US.

In total, 53 per cent of 1,000 people surveyed agreed with the statement that God has a special relationship with America, a figure that rose to 67 per cent among evangelical Christians.

"'God bless America' is more than a song or a prayer for many Americans. It is a belief that God has blessed America beyond what is typical for nations throughout history," explained Ed Stetzer, executive director of LifeWay research. "I am sure that would spawn many theological conversations."