See below for a list of inbound routes from the US to Ireland.

Leaving fromGoing toOperator
Atlanta Dublin Delta Air Lines
Boston Dublin Aer Lingus
Boston Shannon Aer Lingus
Chicago Dublin Aer Lingus
Chicago Dublin American Airlines
Chicago Shannon Aer Lingus
Los Angeles Dublin Aer Lingus
New York (JFK) Dublin Aer Lingus
New York (JFK) Dublin Delta Air Lines
New York (JFK) Shannon Aer Lingus
New York (JFK) Shannon Delta Air Lines
Newark Belfast International Continental Airlines
Newark Dublin Continental Airlines
Newark Shannon Continental Airlines
Orlando Dublin Aer Lingus
Philadelphia Dublin US Airways
San Francisco Dublin Aer Lingus
Washington D.C. Dublin Aer Lingus

If you are travelling from the UK or need to pass through the UK, there is an even greater choice of routes. 

Leaving fromGoing toOperator
Aberdeen Belfast International Flybe
Aberdeen Dublin Ryanair
Birmingham Belfast City Flybe
Birmingham Belfast International bmibaby
Birmingham Cork Aer Arann
Birmingham Cork bmibaby
Birmingham Dublin Aer Lingus
Birmingham Dublin Ryanair
Birmingham Ireland West Airport Knock bmibaby
Blackpool Belfast City a2b airways
Blackpool Belfast International
Blackpool Dublin Ryanair
Bournemouth Dublin Ryanair
Bristol Belfast City Flybe
Bristol Belfast International easyJet
Bristol Cork Aer Arann
Bristol Dublin Aer Lingus
Bristol Dublin Air Southwest
Bristol Dublin Ryanair
Bristol Shannon Ryanair
Cardiff Belfast City Aer Arann
Cardiff Belfast City Air Wales
Cardiff Belfast International bmibaby
Cardiff Cork bmibaby
Cardiff Dublin Aer Arann
Cardiff Dublin Air Wales
Cardiff Dublin Ryanair
Doncaster Dublin Ryanair
Durham Tees Valley Cork bmibaby
Durham Tees Valley Ireland West Airport Knock bmibaby
East Midlands Nottingham Belfast International bmibaby
East Midlands Nottingham City of Derry Ryanair
East Midlands Nottingham Dublin Ryanair
East Midlands Nottingham Shannon Ryanair
Edinburgh Belfast City Flybe
Edinburgh Belfast International easyJet
Edinburgh Cork Aer Arann
Edinburgh Dublin Aer Lingus
Edinburgh Dublin Ryanair
Edinburgh Galway Aer Arann
Exeter Belfast City Flybe
Exeter Cork Air Wales
Exeter Dublin Flybe
Glasgow Prestwick Donegal Aer Arann
Glasgow Prestwick Dublin Ryanair
Glasgow Prestwick Shannon Ryanair
Glasgow Belfast City Flybe
Glasgow Belfast International easyJet
Glasgow City of Derry BA (Loganair)
Glasgow Cork BA (Loganair)
Glasgow Dublin Aer Lingus
Glasgow Dublin BA (Loganair)
Inverness Belfast International easyJet
Isle of Man Belfast City a2b airways
Isle of Man Belfast City Euromanx
Isle of Man Dublin Aer Arann
Isle of Man Dublin Euromanx
Jersey Belfast City Flybe
Jersey Dublin Aer Lingus
Leeds Bradford Belfast City Flybe
Leeds Bradford Belfast International
Leeds Bradford Cork bmi
Leeds Bradford Dublin Ryanair
Liverpool Belfast City Flybe
Liverpool Belfast International easyJet
Liverpool City of Derry Ryanair
Liverpool Cork Ryanair
Liverpool Dublin Aer Lingus
Liverpool Dublin Ryanair
Liverpool Shannon Ryanair
London City Dublin Air France (operated by CityJet)
London Gatwick Belfast City Flybe
London Gatwick Belfast International easyJet
London Gatwick Cork easyJet
London Gatwick Cork Ryanair
London Gatwick Dublin British Airways
London Gatwick Dublin Ryanair
London Gatwick Ireland West Airport Knock easyJet
London Gatwick Ireland West Airport Knock Ryanair
London Gatwick Shannon easyJet
London Gatwick Shannon Ryanair
London Heathrow Belfast City bmi
London Heathrow Cork Aer Lingus
London Heathrow Dublin Aer Lingus
London Heathrow Dublin bmi
London Heathrow Shannon Aer Lingus
London Stansted Belfast International easyJet
London Stansted City of Derry Ryanair
London Stansted Cork Ryanair
London Stansted Dublin Ryanair
London Stansted Ireland West Airport Knock Ryanair
London Stansted Kerry Ryanair
London Stansted Shannon Ryanair
Luton Belfast International easyJet
Luton Dublin Ryanair
Luton Galway Aer Arann
Luton Ireland West Airport Knock Ryanair
Luton Shannon Ryanair
Luton Waterford Aer Arann
Manchester Belfast City British Airways
Manchester Belfast City Flybe
Manchester Belfast International bmibaby
Manchester City of Derry BA (Loganair)
Manchester Cork bmibaby
Manchester Cork British Airways
Manchester Dublin Aer Lingus
Manchester Dublin Luxair
Manchester Dublin Ryanair
Manchester Galway Aer Arann
Manchester Ireland West Airport Knock bmibaby
Manchester Kerry Aer Arann
Manchester Waterford Aer Arann
Newcastle Belfast City Flybe
Newcastle Belfast International easyJet
Newcastle Cork
Newcastle Dublin Ryanair
Newquay Cork Air Wales
Newquay Dublin Air Southwest
Norwich Belfast City Flybe
Norwich Dublin Air Wales
Norwich Dublin Flybe
Plymouth Cork Air Wales
Plymouth Dublin Air Wales
Southampton Belfast City Flybe
Southampton Cork Aer Arann
Southampton Dublin Flybe