Probably less than one in a thousand Americans are even aware that there is an ISIS affiliate in Egypt.
Even fewer know any of the details behind this insurgency because outside of one incident, the American news media has ignored it. Which is why it is interesting.

That one incident you will likely remember - Metrojet Flight 9268.
On 31 October 2015, all 224 died from a bomb planted on an Airbus on en route to Saint Petersburg, Russia. Previously ignored Ansar Bait al-Maqdis claimed responsibility.
After that the news media completely lost interest. Does that mean the attack was a one-off by some fringe group that "got lucky"?
Nope.

Consider this attack in the summer of 2015.


That's an Egyptian naval frigate getting blown up by a missile. This is not the work of amateurs.

Another example is buried in this article about 32 Egyptian soldiers getting ambushed and killed in a single day, early in 2015.

The insurgency has not spread to the tourist hubs of south Sinai, but in pockets of north-east Sinai the army has been powerless to stop militants from frequently establishing their own checkpoints, through which the jihadis have kidnapped and assassinated policemen.

The Sinai insurgency is so popular and wide-spread that the Egyptian army has lost control over the region.

So why is there an insurgency in northern Sinai?
The answer to that question is revealed in a couple maps.

This is the area of ISIS activity in Sinai according to this web site.
Notice the proximity to the Gaza Strip.

This is a map of where the Egyptian government is destroying the homes of thousands of families.
Notice the overlap?

Egypt has demolished more than 3,255 homes and other buildings in the Sinai peninsula in violation of international law, Human Rights Watch says.
Troops began razing homes along the Gaza border in 2013 to create a "buffer zone" and eliminate smuggling tunnels, after a surge in attacks by militants.
But those evicted are given little or no warning, no temporary housing and inadequate compensation, HRW alleges.
The Egyptian government insisted that residents supported the demolitions.

Obviously the residents feel otherwise about their homes being destroyed.

More than 3,600 civilians, security personnel and militants have been killed in the ensuing violence - more than two-thirds of them since the government announced plans for the buffer zone in October 2014 - HRW cited media reports and official statements as saying.

Egypt's counterterrorism tactics in North Sinai amount to a scorched earth policy.

The insurgency started after the Egyptian government decided to massacre 817 unarmed protesters, Tiananmen Square-style, in 2013.
Since then the Egyptian government has launched repeated military offensives, with over 20,000 soldiers, against the insurgency without success.

More and more, the army is fighting the militants outside their stronghold in the north. In February and March it conducted raids on hideouts in the desert of central Sinai. This month, after several failed attempts, it says it took the insurgents’ base in Jebel Halal, a mountainous area. Israel warns that IS has put up roadblocks in central Sinai to capture soldiers and tourists.

Just two weeks ago a full-scale battle claimed the lives of 23 Egyptian soldiers.
It's hard to say exactly what is going on in Sinai because the Egyptian military does not allow journalists or any independent observers from entering.

The Egyptian government has an interest in maintaining its narrative of successfully fighting terror. Between 2011 and 2015, Cairo received $6.5bn in US military aid.
The Egyptian military has reported more than 6,000 deaths in northern Sinai since mid-2013. That figure greatly exceeds the number of militants in the area: estimated at no more than 1,000, according to the DC-based think-tank, the Tahrir Institute for Middle East Policy.

However, the Egyptian government is losing its ability to maintain the silence on this insurgency because the fighting and bombings have leaked outside of Sinai and into the rest of Egypt. In April and May terrorists slaughtered Coptic Christians in northern Egypt. Cairo is seeing bombings on a monthly basis.
In response the Egyptian military government has responded in the only way it knows how - an iron fist.

In response to the attacks, the Egyptian government, led by President Abdul Fattah el-Sisi, declared a new and more sweeping state of emergency that further increases the scope of police detentions, suspends many constitutional rights, and further limits the right to assembly....
Just as Wilayat Sinai is taking its fight across the canal to the mainland, the Egyptian government is increasingly utilizing the counterinsurgent tactics that were once reserved for the Sinai in mainland Egypt.11 Far from effectively combating insurgent groups like Wilayat Sinai, the sort of scorched earth tactics used in the Sinai risks not only aiding Wilayat Sinai, but more worryingly for the security of Egypt, these tactics are creating new operational spaces for a range of emergent insurgent organizations. Some of these emergent groups, like the Hasm Movement,c are far more moderate than the Islamic State and more capable of tapping into growing discontent among the Egyptian population. While formidable, Wilayat Sinai’s extreme views will limit its appeal and ability to put down deep roots in mainland Egypt. This may not be the case for emergent groups who have moderate views and a more discriminate approach to the use of violence. However, these groups will be able to learn from Wilayat Sinai’s experience with fighting the Egyptian army and police forces in the Sinai. The war in the Sinai has clearly demonstrated the very real limitations and vulnerabilities of the Egyptian army and police forces.

As long as the Egyptian government relies on collective punishment, arbitrary and mass arrests of villagers, indefinite detention, and extrajudicial execution of detainees, this insurgency will only get worse.