During his two-day visit the Foreign Secretary will meet Vice President Mike Pence, National Security Advisor John Bolton and Congressional foreign policy leaders.
As well as Iran, Mr Johnson’s talks are expected to cover North Korea – ahead of President Donald Trump’s planned meeting with Kim Jong Un – and the situation in Syria.
Ahead of his trip, Mr Johnson said: “On so many of the world’s foreign policy challenges the UK and US are in lockstep.
“We’ve seen this recently with the response to the poisonings in Salisbury, our strong response to Assad’s use of chemical weapons in Syria, and the effort to denuclearise North Korea.
“The UK, US and European partners are also united in our effort to tackle the kind of Iranian behaviour that makes the Middle East region less secure – its cyber activities, its support for groups like Hezbollah, and its dangerous missile programme, which is arming Houthi militias in Yemen.”
Britain remains committed the nuclear deal Iran signed with world powers in 2015.
Under its terms Iran is committed to a peaceful nuclear energy programme.
But Mr Trump has been a vocal critic of the agreement and in January issued an ultimatum to “either fix the deal’s disastrous flaws, or the United States will withdraw” when it comes up for renewal on 12 May.
The President is critical of Iran’s failure to address its ballistic missile programme, the terms by which inspectors visit suspect Iranian sites, and “sunset” clauses under which some terms expire.
Britain, France and Germany – the three European countries that signed the deal – have repeatedly tried to persuade Trump not to abandon it.
More from Boris Johnson
Boris Johnson backs Iran nuclear deal after Israel claims
Johnson ‘repeats call for amnesty for some illegal immigrants’ in wake of Windrush
Boris Johnson defends strikes on ‘barbaric’ Bashar al Assad
Boris Johnson criticised for congratulating Hungary’s Viktor Orban
Tories attack Russia and ‘useful idiot’ Jeremy Corbyn over Salisbury poisoning
Nerve agent attack: Boris Johnson accuses Jeremy Corbyn of ‘playing Russia’s game’
Earlier this month Mr Johnson stressed the importance of keeping the deal “while building on it in order to take account of the legitimate concerns of the US”.
The European Union has said the deal “is working and it needs to be preserved”.