Can First Cousins Marry In Idaho? (Explained)

It is currently illegal for first cousins to marry in Idaho.

First cousins once removed and other more distant relationships are allowed.

Idaho does not recognize first cousin marriages that are conducted in other states where the union is legal.

This article looks at what you need to know about cousin marriages in the state.

What Do The Idaho Marriage Laws Say About First Cousins?

Idaho marriage laws have separate sections that list relationships that can’t marry in the state.

They explicitly name first cousins in this section:

MARRIAGES BETWEEN FIRST COUSINS. All marriages between first cousins are prohibited.

Idaho marriage laws

Note that they don’t name “first cousins once removed”. As this relationship isn’t mentioned in the statute, we can assume that it is permitted.

Who else can’t marry in Idaho?

The other section has quite a long list of relationships that are prohibited.

Marriages between parents and children, ancestors and descendants of every degree, and between brothers and sisters of the half as well as the whole blood, and between uncles and nieces, or aunts and nephews.

Idaho marriage laws

Blanket ban

Some other states generally don’t allow first cousin marriage but have some allowances based on age or other criteria.

In contrast, Idaho has a blanket ban within the state. There are no special exceptions.

How first cousins are legal in some other states

Many other states have similar long lists of prohibited relationships in their marriage laws. But they stop short of mentioning first cousins.

Their laws don’t say explicitly that first cousins can marry. They simply don’t mention the relationship in their restrictions.

That’s why these marriages are legal in these states.

Marriage In Idaho

Types Of Cousins That Can Get Married In Idaho

Other types of cousins can get married in Idaho.

For example, marriages between first cousins once removed are permitted. The children of your first cousins are your first cousins once removed.

If you’re not sure what the different types of relationships mean, check out the links below to articles with easy-to-understand explanations.

“First cousins once removed” in Idaho laws

You may be thinking that the legislators simply couldn’t be bothered listing the different types of first cousins. Are we sure that they didn’t mean to include the “once removed” type?

Well, there are other sections of Idaho family law that get specific about these relationships.

One example is from the state’s regulations on emergency assistance for families and children. The relatives of a child include (there are more):

Brother, sister, aunt, uncle, nephew, niece, first cousin or first cousin once removed

Cornell Law School

I mention this just to note that the legislators of marriage law didn’t just forget that “first removed” exists.

Does The Idaho Marriage Application Form Ask If You’re Related?

Some U.S. states have a section in their marriage application forms where the couple must state whether they have a blood relationship.

You can see an example in our article on first cousin marriage in Georgia.

We reviewed the online form from Naz Perce County in 2022. There is no such question present.

Does Idaho Recognize First Cousin Marriages From Other States?

At the time of writing, Idaho does not recognize first cousin marriages conducted in other states.

The state only recognizes marriages that could have been lawfully established in Idaho.

Do Nearby States Allow First Cousins To Marry?

Idaho is bordered by Montana, Nevada, Oregon, Washington, and Wyoming. None of these states allow first cousins to marry.

California and Colorado are probably the nearest options for first cousins to marry legally.

Idaho Neighbors

Looking for a destination wedding spot?

Do you live in a state or country where first cousin marriage is legal and you simply wanted to visit Idaho for a ceremony and vacation?

Consider these other states as alternative options in the region!

Looking to relocate?

Some first cousin couples move lock, stock, and barrel to another state where their marriage will be legal.

Review your options and future plans carefully. You may wish to sit down with an attorney to consider the implications. Some states in the U.S. will not recognize legal marriages from other states.

Roman Catholic Marriages

Even if close cousins move to another state that allows their civil marriage, they will face separate hurdles if they want a wedding in a Roman Catholic church.

Historically, the Catholic Church hasn’t encouraged first cousin marriages. However, the church laws have been relaxed somewhat in recent years.

There is a process that first cousins need to go through with the hierarchy in order to get permission to marry in a church ceremony. This is known as a dispensation.

We go into this in detail in our article that explains first cousins (scroll down to the bottom).

What about second cousins?

Second cousins (and further out) don’t need to get special permission for a Catholic Church marriage.

Frequently Asked Questions

Here are some quick answers to common questions.

Does Idaho allow relatives to marry?

Idaho does not allow close relatives to marry.

More distant relatives such as second cousins are allowed to marry in the state.

Can you marry a sibling in Idaho?

Idaho does not allow siblings to marry. Half-siblings are also not allowed to marry in the state.

Is it legal to marry your second cousin in Idaho?

Marriage between second cousins is legal in Idaho.

Other Strange Laws Around Marriage In Idaho

It’s not all that surprising that Idaho is quite restrictive in its cousin marriage laws.

There are some other somewhat archaic laws surrounding marriage. For example, adultery is a felony in the state. That isn’t even an archaic law, it was established in 1972.

It’s true that felony is also illegal in plenty of other states. But only a handful class it as an actual felony with serious jail time.

Idaho adulterers could face up to three years in the slammer!

To be fair to the Gem State [I like to use nicknames for states, but does anybody ever call it that?], this offence is rarely prosecuted by the authorities.


The codes and laws referenced in this article may not be the most recent version. Idaho may have more current or accurate information.

We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on other sites. Please check official sources.

Margaret created a family tree on a genealogy website in 2012. She purchased her first DNA kit in 2017. She created this website to share insights and how-to guides on DNA, genealogy, and family research.

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