There is no definitive answer to this question as it depends on how you measure "least amount." Some states have fewer public charging stations than others, but this doesn't take into account the number of private charging stations available. Additionally, some states are more populous than others, so even if they have fewer public charging stations, there may be more people living there who could use them.
That said, California probably has the fewest public charging stations relative to its population. The state has a little over 39 million residents, but only about 1,500 public charging stations. This works out to about 26 people per station. Compare that to North Dakota, which has about 760,000 residents and only 16 public charging stations. That's about 47,000 people per station.
So, while it's hard to say definitively which state has the least amount of electric vehicle charging stations, California is a good contender.