

| Iceland | Anskar, Thorlac |
| Idaho | Our Lady of Limerick |
| Illinois | Our Lady of the Universe |
| Illness (mental) | Dymphna |
| Immigrants | Frances Xavier Cabrini |
| Imperia Italy | Leonard of Port Maurice |
| Impossible Cases | Rita of Cascia |
| India | Mary, Patron of India, Frances Xavier Cabrini, Rose of Lima, Thomas, Apostle |
| Indian missions in Ecuador | Our Lady of Agua Santa de Baņos |
| Indiana | Our Lady of Providence |
| Infantry | Martin of Tours |
| Infantry, Spanish | Immaculate Conception of Mary |
| Infertility | Rita of Cascia |
| Information Workers | Archangel Gabriel |
| Innkeepers | Gentian |
| Innocent people (falsely accused) | Raymond Nonnatus |
| Insanity | Dymphna |
| Invalids | Roch |
| Iowa | Mary of Nazareth |
| Ireland | Patrick, Columba, Bridgid of Ireland |
| Isle of Man | Maughold |
| Istanbul (Constantinople) | John Chrysostom, George, Roch |
| Istanbul, Turkey; Constantinople | George, John de Britto, Roch |
| Italy | Bernardine of Siena, Catherine of Siena, Francis of Assisi, Our Lady of Loreto, Our Lady of Perpetual Help, Our Lady of the Snows |
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