Question
I have been battling this weed forever. Most weed killers only cause the ivy to chuckle at you.
Got a viable strategy?  The location is northeastern Massachusetts.

Answer
Ivy can be extremely difficult to eradicate from a lawn (like I need to tell you this ?). There are no current herbicides rated for ivy eradication, short of round-up (glysophate) which will also kill grass.

One drastic option is of course to kill the entire lawn with round-up and wait to ensure the ivy is gone, and then reseed (probably not your first choice?)

What we did when we had similar problems, two people walked through the lawn with two heavy duty cardboard pieces and a bottle of round-up. one person would press the pieces together around the stem of the weed - but above the grass - and the other would spray the weed with round-up. keep the board a few seconds to avoid dripping. Then remove cardboard and on to next spot. Keep going. Avoid saturating the leaves too much or it will drip onto lawn.

Some damage to grass must be expected and some individual spots may need overseeding.

Then be very vigillant. go after the weed whereever you see it. Even the smallest sprout should be pulled. This will rob the plants ability to photosynthesize, e.g. convert sun energy into plant energy. If you keep at it, and at it, and at it, you will eradicate the plant.

After initial spraying, go through your lawn several times per week very systematically, starting at the same point every time. Look for all signs of weeds and control. At this point, even breaking off small sprouts every day is enough to keep a weakened weed on the run. Slowly there will be less and less weeds, but if you keep at it you will get them all.

I realise this is not easy, but as said, ivy is not an easy weed to control in lawns.