Continue into Salt Lake City and you are unlikely to remain in the dark for long. Almost anyone will explain that it is a reference to the words of Brigham Young, leader of the first Mormon pioneers to reach the valley in 1847. 'This is the right place,' he said, seeing it for the first time.
And indeed, at least for Mormons, his words remain apt today. Although Brigham Young's dream of creating a theocracy within the United States may not have quite come about, Utah today remains a place where political and social life and the very conservative doctrine of his church are almost inseparable.
It is a presence that has been especially evident in the run up to this Easter. Last weekend 6,500 members of the church - formally the Church of Jesus Christ of Latter-Day Saints - swarmed into the city for their annual conference. On Tuesday they celebrated the centenary of its spired temple in the heart of the city. With a worldwide membership of 8.4 million, the church also announced plans to build several new temples, including one in Preston, England. Today it has only one in Britain, close to Gatwick airport.
But suggest to church officials that they, rather than the occupants of the somewhat eclipsed State Capitol a few blocks from the temple, actually run the state's affairs and you will be bombarded with denials. It is simply a case of benign influence, they say.
'Some say that the church runs the state but that's not true at all,' says Don LeFevre, spokesman for the church with an office on the 25th floor of its administration building, the tallest in town. 'It is just very normal that in a state where more than 70 per cent of its inhabitants belong to the church there should be some influence by those individuals.'
In fact, nearly 150 years after Young and his first contingent of 147 pioneers arrived in the valley, almost three-quarters of Utah's population are Mormons. They account for 90 per cent of those who describe themselves as religious. The next-largest religious group in the state are Catholics, who account for only 3 per cent of state's 1.8 million inhabitants.
Nor are the members of the State Capitol likely to cross the church. Nine out of 10 of the legislators are practising Mormons and regularly hold meetings with church leaders before taking important votes. The state's newly elected Governor, Mike Leavitt, is a Mormon too. On taking office he pledged to seek divine guidance on important issues. The church also owns one of the state's main television stations, KKSL.
Mr LeFevre, whose own grandfather was among the first Mormon settlers here, says the church never takes political sides. When matters of moral teaching arise, however, it will always stir. 'Clearly we have a right and indeed an obligation to speak up on moral issues that we believe are important, like pornography, alcohol use and so on. But we never seek to impose our will,' he explains.
The Mormon doctrine is indeed restrictive, arguably even authoritarian. Members can be excommunicated for such sins as pre-marital sex or infidelity. They are barred from drinking not just alcohol but even coffee, tea and Coca Cola. They are expected to participate in almost daily community activities. In theory they must also donate 10 per cent of their pre-tax income to the church. Polygamy, for which Mormons were once famed, and persecuted, was outlawed by the official church in the 1890s.
The only recorded occasion when state legislators have defied the Mormon establishment was 60 years ago when they supported the national repeal of probihition. Here today, however, alcohol sales remain strictly controlled. In the same vein, the church celebrated a victory last autumn when the state government moved to ban betting on horses.
For drinkers and gamblers, at least, the influence of the Mormons can only be oppressive. Equally, however, Salt Lake City is a strikingly neat city, in a spectacular setting and with few of the urban slums so familiar in other American cities. 'If I have a problem it is the state control of alcohol sales, that is the only real inconvenience,' says Linda MacMahon, a non-Mormon who moved to the city 20 years ago from North Carolina.'