It has been around 50 years since the US Supreme Court deemed laws against interracial marriages unconstitutional, allowing couples to get married even if they were not of the same racial background all over the US. Since then the % of interracial marriages in the US has risen from around 3% in the 1960's to 17% in 2015 and the number has been steadily on the rise.
There are a few factors that can be directly attributed to this increase.
Interracial marriages were far more likely to happen in urban populations than in rural ones. The reason behind this is the ethnic diversity found in an urban area is far greater than in rural regions, encouraging greater interaction between people of different ethnic origin. The flipside is the restrictive nature of rural areas, where people are likely to know each other very well and the opinions of neighbors have a heavy bearing on perspectives. In Honolulu, Hawaii, the % of interracial marriages stood at 42% of all marriages, but on the flipside, in Jackson, Mississippi, it was just 3%, showing how the concentration of different populations in a region, as well as the conservative history of that region can influence the decision to marry someone from a different race.
2. Lack of Suitable Partners from Same Race
Black Women have a lower overall marriage rate compared to other women, because of the high rate of unemployment and convictions among black men. Despite this, Black Women are in the minority where interracial marriages are concerned, preferring often to stay single instead of marrying outside their race.
Interracial marriages were more common among people who had a proper educational background. Areas that had better educational facilities and resources had a higher rate of intermarriage. Considering the influx of foreign students in the US, where a lot of people of different nationalities and cultures are able to mingle, often with American students, is a major contributor to interracial marriages.
The black community has the highest rate of acceptance of interracial marriages, while this number decreases when it comes to whites and hispanics. Certain types of intermarriage are less acceptable to the American population, with only 66% acceptance for interracial marriages involving black people, and a much higher acceptance rate for whites and hispanics outside their own race.
5. Migration Trends
Certain ethnic groups are more likely to settle down in certain areas, creating a culture bubble in their localities. Where hispanic immigration is more common, white-hispanic marriages are much more common. The Asian influence on the west coast is a good example of this. White-Asian marriages are one of the biggest contributors to interracial marriages as of 2015.
There are many smaller factors to consider in the above, with economic, social and political reasons among them. The biggest contributor to interracial marriage has historically been between whites and hispanics. Coming from a similar racial background has encouraged intermarriage among them, but the others are catching up slowly.