Achill-henge is a 2011 concrete structure on Achill Island off the northwest coast of County Mayo, Ireland.

[1] Mayo County Council requested a court order to force McNamara to remove the edifice as it had been built without planning permission.

[2] The High Court required McNamara to cease further work on the site, and as he was found to be in breach of this, upheld the Council's decision.

Joe McNamara is noted in Ireland for a series of protests against Anglo-Irish Bank and the government's handling of the Irish financial crisis.

In particular, he drove a concrete mixer truck into the gates of the Irish parliament building Leinster House, causing minor damage to the paintwork of the gateway.