It is time for a backyard construction project on an island with a resident population of one and a transient population of 4.3 million.

The one will never notice, unless she has eyes in the back of her large green head, but the 4.3 million people who visit the Statue of Liberty every year probably will.

The project, a $70 million museum, is intended to make the visitors’ time on Liberty Island more meaningful, more enjoyable and perhaps less crowded. The museum, to be announced at a ceremony on Thursday, has been designed to absorb the crush of people arriving on ferries that dock every 20 to 30 minutes.