An eastern Long Island widow and her 14-year-old have been missing for almost three weeks after a trip to New York City to see a play.

Iona Costello, 51, and her daughter Emily, from Greenport, were going into the city when they were last seen on March 30 near their home in the the wealthy seaside village.

Their car was found in a parking garage on 42nd street in Manhattan, but the pair, who often went into the city for theater and art museums, left no other trace of their whereabouts.

Iona Costello, 51 (right) and her 14-year-old daughter Emily (left) have been missing for almost three weeks after last being seen on March 30 near their home in the wealthy seaside village of Greenport

The pair often go to shows and museums in New York City, but relatives have filed a missing person report after Emily did not return to her East Hampton school from Spring Break

Relatives of the family, who own a horse farm on Long Island's North Fork, reported them missing on Tuesday.

'She said she was going to Manhattan for Easter,' Iona's mother Diana Malcolmson, 80, told Daily Mail Online.

The grandmother, who lives in nearby Shelter Island, New York, said police told her that surveillance footage from the parking garage showed Mrs Costello and Emily walking away from their car on March 30, holding suitcases and laughing.

She said that she spoke regularly with her daughter, but had not heard about any plans for extended vacations.

Iona Costello also has family in England, though they have not heard from her, according to Southold Local.

While trips into New York were fairly normal, Emily being out of school is not.

The ninth grader had been scheduled to return to Ross School in East Hampton from her Spring Break this past Tuesday.

Iona Costello's husband George, the co-owner of Costello Marine in Greenport, died from a heart attack in 2012

Police said that they do not expect foul play and have no hard evidence suggesting that the Costellos may be in danger

The mother had told workers at her farm that she would be 'back on Tuesday' but did not return on March 31st, April 7th or April 14th.

Workers at the horse farm say it is strange for Mrs Costello not to be in contact with them about raising the animals.

Southold police Chief of Police Martin Flatley told Daily Mail Online that his force do not expect any foul play.

He said that he does not currently have any hard evidence to point to the mother and daughter being in danger.

Relative Jane Costello said that calls to both Iona's and Emily's phones go straight to voicemail.

Police still say they do not expect any foul play in the case, though workers at the Costello's North Fork farm say that she would normally be in contact about the business's affairs

Workers at the farm, which also includes cows, said that Mrs Costello told them she would be 'back on Tuesday'

Mrs Costello was a well-known equestrian in eastern Long Island, according to the East Hampton Star.

Iona's husband George, co-owner of construction company Costello Marine in Greenport, died at the age of 63 a heart attack in 2012.

The pair had married in 1999.

It is not believed that the Costellos owned any property in New York, according to Chief Flatley, though authorities are now looking at a wider circle of relatives that may know about their movements in the city.

A spokesperson for the NYPD said that city police are working in conjunction with Southold officers, but have not yet received any sightings of the mother and daughter.